questions on cutting, prepping, & painting acrylic

[iSign]

The first attachment will be the proof of my final product. I wanted to do most of this sign as a single 3D routed HDU sign, and even got as far as programing (& test running a small sample of) the woven mat background, which is an actual Bamboo product...

...but my client really wants to go with using the bamboo mat itself (second attachment) & he has been informed, and accepted that I can not warranty the life expectancy of the sign as a result. That sort of texture is of common interest around here, so I don't mind the time spent on creating a routing file for it, or the chance to experiment with using the actual product on a sign where the end user has taken on some of the risk for experimentation...

But anyway, now that you have some of the initial background information, the plan at this stage is to use an adhesive & bond the mat to 1/4" acrylic. This will then get a sealer/stain. I will assemble a wood frame, routed like a picture frame from the back to protect & hide the edges of the mat.

Here is where I have some acrylic questions. I plan to bond a lot of acrylic to the stained mat & for this I plan to use liquid nails. If anyone has suggestions, or cautionary information related to this, I'm interested, but i don't have too many concerns with that step...

The steps I'm unsure of is the painting of the acrylic, and the bonding on multiple layers of acrylic. I know the acrylic cement needs to melt raw acrylic, but I also know pre-painting items before bonding means I can spray them, so now i have questions about bonding them, spraying thenm, and rolling paint on the faces.

I think the best plan I can come up with so far (without starting over) is to cement everything together & spray all the bamboo stuff dark green, & then roll on 2 coats of the light green just on the face of the top layer... and for the lettering, bond with acrylic cement, spray the burgundy, & roll on two coats of the imitation gold color.

Now, I am definitely open to feedback on those ideas. The most obvious alternative to me is to forget the acrylic cement, spray all my colors, & then bond with some other adhesive that doesn't mind bonding painted surfaces... which brings me to my paint questions...

I am not a paint expert by any means.. I've rolled 1-shot on panels for many years, & I've also painted small wood or PVC letters with a foam brush... my only spraying experiences are a lifetime of playing with rattle-can spray paints, and a little bit of experience spraying Porter latex with an HVLP gun on HDU...

so, on the all important paint questions, what surface prep might I need for acrylic? Just clean & free of dust, or do i need to scuff it with a 600 grit or steel wool? What paints can people give me feedback on... enamel spray paint? Latex enamel thinned for HVLP? Rolling on 1-shot?

..and of course if I do go with spraying the different colored parts separately, what adhesive can be recommended for bonding the unpainted acrylic backs of letters to the painted acrylic faces of their outlines pieces?

the last round of questions pertains to some of the other unforeseen challenges in the largest batch of acrylic lettering I've ever cut... I used a carpet tape for holding down the acrylic. Some I peeled the paper liner before routing, some not... but in either case, the "sawdust" sticks to the edges where there was tape, because the process of cutting seems to get adhesive on the edges, or mixed in with the sawdust & it doesn't blow off with the compressor like I hoped... so it becomes a bit of a chore to wipe off... anyway, I pretty much have everything cleaned up, but if I wanted to get them even cleaner, I wondered about soaking the letters in something that breaks down that adhesive residue but doesn't hurt the acrylic...


..as for that last question, if the right answer would have been to paint first, mask, then rout, or perhaps to stock some kind of sheet version of 3M VHB tape & have that applied to acrylic before routing... well, go ahead and advise me of any tips and tricks any of you have to offer, even if it means I'm already doing it wrong... it's never too late to learn, and I'm the first to admit I have a lot to learn on my relatively new foray into the world of CNC and to a slightly lesser degree, the world of paint.

The last few attached pics show the acrylic pieces in there slightly sticky sawdust covered state, before peeling paper, or carpet tape... and then the semi complete layout of unpainted pieces (minus the uncut web address) ...and following a quick edit, I've added a photo of the clients old sandblasted sign, which I've never seen in person but copied from this pic...


*EDIT* decided to add another pic because the lighting in my acrylic pieces pic is poor, and I wanted to show that where my layer of leaves overlaps the bamboo stalks, I created a slight outline contour for each leaf section, and welded that to the bamboo stalks, so there are no leaf sections floating unsupported out over the background... just to help give a complete picture of what I'm trying to do...

 

[GB2]

Hmm....this is a little complicated but my first thought is that you're just going to have to try out some of those methods on some scrap and use the one you are most comfortable with. You know there's no real wrong or right way, just the way that you can accomplish the task in the most efficient manner. By the way, is this for interior or exterior use?

Now, if I understand correctly, you have double layer lettering that you're unsure of bonding/painting, painting/bonding. I think I would agree with you and my first attempt, now that all the letters are already cut, would be to use WeldOn #16 to bond all the letters, spray them all with Krylon Fusion Burgandy, then top coat the letters with the Gold in a paint of your choice. The same treatment with the green elements.

You possibly could have done some coloring before routing by either flood coating with vinyl or painting and masking, but then what about the edges? You could also pre-apply a wide double sided adhesive but that is something you'd have to have available and the wide widths are expensive.

If you have to do any other bonding with painted or unpainted pieces, as much as I hate going near the stuff, silicone works very well.

As far as using carpet tape, I think that is a big error, especially if it is the run of the mill type in a carpet store or Home Depot. That stuff is a hazard, you need a good tape like InterTape 591 and then you won't have those issues. If you need a chemical helper to clean the adhesive residue, the only thing I'd try on that acrylic is Rapid Adhesive Remover.

I think that's going to look great when you're done though! I hope it's profitable too!

 

[Gino]

Hope I can do this without being confusing, but I might be jumping around compared to the order you wrote your request.

I would WeldOn #16 your acrylics together. I’d try to keep the paint off the sections to be glued. If you aren’t going to guarantee the sign, you might be able to get away with some Krylon for plastic use rattle cans. I’ve used it for quite a few applications and most of that being red and it’s held up for almost 4 years now.

I’m not a fan of liquid nails because when it dries it becomes super hard and that’s Okay for wood [which its intended use is] but for plastic, you might want to think about using small pins by drilling out the back of the finished letter, gluing in a nail [with the head clipped off] and then setting it into the wood backer behind the bamboo mat.

What you’re doing is what we used to do when we sandblasted signs with varying layers. However, we always handpainted in all of those areas… which is time consuming, but very nice when finished. I’m afraid Doug, that there isn’t a quick fix to getting your layered colors down without cutting some corners which might cut the integrity of your craftsmanship.

I have another idea, but I’d like to see how you want to handle the small returns of these letters It might’ve been interesting to cut colored acrylic and painted the face only… the color of your choice, thus creating another relief look.

 

[Ken]

Hey...
Krylon does make a paint specifically for plastics. I've used it on PVC and styrene with good results. It comes in spray bombs with a limited choice of colors. I've never tried it on acrylic. But they claim no surface prep necessary other than cleanliness.
Rustolem also now makes an "all surface" spray paint that I have used on metal, aluminum and wood. Again, limited color choices and spray cans.
I'm wondering if you could use a spray adhesive when cutting your acrylic to avoid the sticky mess you describe. It would avoid having to cut thru the paper and perhaps come out cleaner.
I'm betting you dont want to do this....but....
Cutting a duplicate set of text and bamboo (top layers) would allow you to do your overlay, paint over everything. Remove the top layer(s) and replace with your nicely painted acrylic pieces using a glue designed for acrylic.
Interesting job.
Cheers!
Ken
Sorry...you don't need a duplicate set of the upper layer of acrylic. Use some thin double sided tape. ..stick them down...paint your lower level of acrylic...remove the top and paint again with your upper color.

 

[artbot]

if you are experimenting with some adhesives. the weld-on is good. but will create a brittle matrix. liquid nails is flat out a no. for that, use loctite universal T.A.C. (available at lowe's!) it is by far the most impressive one part adhesive i've every come across. it's very high viscosity. if you are going to use it a lot, i'd get a cheap electric caulking gun from HF.

as for the painting, i'd hit with a plastic primer before hand (about three quick coats). it will gap fill, giving it a more monolithic look, and have a softer sandable surface that will let your pigment go down much more attractively.

 

[Billct2]

If I understand correctly,the carpet tape is what you use to hold the letters while routing and it leaves residue? You can clean that with mineral spirits or alcohol. For the painting/bonding of the acrylic letters you could use "spray" mask or transfer tape on those areas where the letters will be bonded, that will give you direct acrylic to acrylic bonding which is the most durable.

 

[signmeup]

Paint is essencially pigment and glue mixed together. You could glue the painted parts with the paint itself. After all, if the paint won't stick to the letters why bother using it at all?

Silicone seems like the best idea for attaching the parts to the matt.

I don't have a router so I would have blasted the design really deep then hand carved the bamboo stems and leaves and added the lettering at the end. (I would've V carved the letters into a raised contour)

I think the bamboo matt will fade in the sun pretty quickly and that your parts will fall off just after that happens. I'm just a big ball of negativity this morning aren't I?

 

[GB2]

Hey...would it be possible to use a piece of clear acrylic over that bamboo and bond the other pieces to that? Or maybe you could pour that clear bar top stuff over it first? It would be a shame to do this nice sign and have the bamboo fail in 6 months, then what, do it all over? Gino's thought about pinning the letters is good but that's a lot of tiny letters and if you pin them it would be nice if you could somehow remove them in the future, replace the bamboo and then put them back.

 

[Just Another Sign Guy]

sorry Isign I dont have the time to answer this question in the detail it deserves. but as always feel free to call me if you have some specific questions.

for painting acrylic there is only one product i really like Lacryll (spl?) i know pacific coast paint sells it and they will even custom mix colors for you and put it into spray cans (or at least they used to).

for painting cut letters here is what i like to do. take a sheet of HIGH TAC transfer tape with the adhesive facing up and stick the bottoms of the letters to the tape. then i spray the letters the color of the returns (unless i am using a substrate that the color is the same as the return). then when dry i paint the faces. for me it takes much more time to paint the returns than the faces so i would rather get that part of the job out of the way with the spray process.

obviously you can also spray the sheet before you cut it so the faces are painted then mask and then cut, leaving the premask on the faces and then spray the returns...in my experience it is more work than it is worth...cleaning runs that get under the face etc.

acrylic in my experience always leaves a little debris that needs to be cleaned up. but yours look excessive. i would say it is a result of hte carpet tape. i only use carpet tape when in a pinch and nothing else is available. i would much rather use a double sided masking tape..it is also possible with your router to cut right through the substrate and not through the tape..it truly is possible.

but for acrylic letters what i have always done is blow the pieces off with compressed air as i pull them off the table this usually gets most of the debris but then i throw them into a bucket of water and when they are all in there i wipe them off one by one the reason i do this is i am preparing for paint and dont want any 'stuff' on them at all.

just be happy you are not having to polish the edges on your cut letters for picky clients.

i skimmed your initial post but i would be worried about mounting directly to that mat if that is your idea. what i would do is put a ridgid substrate behind the mat or cover a ridgid substrate with the mat. and then adhere the cut elements with posts through the mat. the post method wouldnt be too difficult with a little preplanning. cut your letters in reverse and then have the router drill the holes for clear acrylic rod of the correct thickness that will work for your project. and then in the substrate you place behind or over the mat have the router drill corresponding holes for the studs. insert studs into backs of letters with a dollop of adhesive and then place the studs into the mounting piece without adhesive if you wish to have the option of replacing annually (or multi annually) to replace the grass mat

 

[signage]

My first question would be what is the life of those Bamboo mats?

After this answer if feasible I would you give you my suggestion!

 

[3dsignpros]

adhereing bamboo mats to acrylic?

That is an interesting concept...as far as painting the acrylic its simple...1. wipe down the acrylic with denatured alcohol 2. tie bond the acrylic with an hplv spray gun (i use a devilbiss) 3. if using one shot reduce with paint reducer 4. spray your material wait 24 to 48 hours depending on temperature then glue up your material(s). I have yet to glue up bamboo so Iam intersted in such a project. Hope i helped out a bit

 

[andy]

The first thing I would do is take the bamboo matting into the booth and give it at least two heavy coats of UV stabilised two pack lacquer. The first coat should be almost fully absorbed by the wood fibres, the second coat should do the final top seal. This method will fully waterproof the bamboo and prevent aging from sunlight; in theory the mat should last years.

For bonding the painted acrylics together the easiest and cleanest method would be to use a clear 3M VHB tape, one rated for sign applications. This will stick like $hit to an acrylic blanket. If you have lacquered the bamboo to a good finish then there is no reason why pads of VHB won't be suitable for fixing the acrylic letters in place; there isn't an awful lot of weight involved and this VHB method is quick and doesn't involve splodges of liquid adhesive going everywhere.

For the painting process you could nip down to your local auto paint factors; there is a clear plastic primer/ binder product available which works on just about any kind of plastic. A coat of this will fully bind to the acrylic leaving a paint receptive surface for the following colour coats.

Personally I would avoid rattle cans if at all possible, even the cheapest gravity fed spray gun will give you an better finish and make painting much easier, even better, get a small touch up gun, these are perfect for paint small, complicated items like lettering. If you go down the spray gun route you can use many more kinds of paint and the savings buying paint in liquid cans rather than aerosol tins is considerable.

 

[3dsignpros]

adhereing bamboo mats to acrylic?

That is an interesting concept...as far as painting the acrylic its simple...1. wipe down the acrylic with denatured alcohol 2. tie bond the acrylic with an hplv spray gun (i use a devilbiss) 3. if using one shot reduce with paint reducer 4. spray your material wait 24 to 48 hours depending on temperature then glue up your material(s). I have yet to glue up bamboo so Iam intersted in such a project. Hope i helped out a bit

 

[artbot]

after rereading ... definitely clear coat that bamboo. just a few coats of precat lacquer or cab lacquer in a medium hand rubbed. it will be difficult to buff out with all the texture so i'd go semi, and sand with 600 only.

 

[iSign]

lots of great replies.. I'm working today & can't write for very long but the bamboo has been used for over 4 years on all the walls on this clients vacation rental property. He coated it with a particular product that he offered to provide to me during the "no warranty" discussion... but then he brought it in an unlabeled glass jar, so I need to get specs from him on that product.

I have routed pin mount holes in substrates & the back of letters many times, but this did seem like too many letters, so i will live dangerously & try my luck with one of the suggestions above.

I wanted to put may clear acrylic over the bamboo & suggested that to the client, but he wasn't at all wanting that..

I will be back to give more info, feedback or replies, as time permits or progress is made..

thanks again everyone!!!!

 

[signage]

Ok what I was thinking was to use exterior contact cement and glue the Bamboo mat to whatever you where planning to use as a backer. Then Clear the Bamboo, then i would make a recess for the graphic and letters in the bamboo/backer and use VHB tape to adhere the acrylic.