CoachWhite 0 Posted April 3, 2016 We have our first exterior lighted sign job and we need some help. What is the best way to remove existing paint so that we can apply vinyl? Thank you. Share this post Link to post Share on other sites
Topper 61 Posted April 4, 2016 What is the paint on? I'm no expert but I would replace the substrate. Or you can try paint thinner/remover and scrape it off. Easier said then done... 1 Share this post Link to post Share on other sites
slice&dice 2,450 Posted April 4, 2016 Due to 'ghosting' of existing (old) lettering, it's normally not possible to reuse acrylic sheets that have been in a lighted sign for years. 1 Share this post Link to post Share on other sites
CoachWhite 0 Posted April 4, 2016 The owners know that we have a 50/50 chance of get the old paint off or buy new panels. My concern for using paint thinner is staining. I read that if you allow Break fluid Dot 3 sit for a while it will remove the paint with little work or having a smearing issue. Share this post Link to post Share on other sites
CoachWhite 0 Posted April 4, 2016 The paint is on an Acrylic/Fiberglass sigh. It was hand painted then a white sprayed background. Share this post Link to post Share on other sites
darcshadow 1,626 Posted April 4, 2016 Acrylic and Fiberglass are two very different things. There are several fiberglass specific paint removers. But you are likely dealing with Acrylic which is going to be difficult getting the paint off without etching the acrylic or making it cloudy. Do you know what kind of paint was used? That will make a difference as to what work. There are also some amazing acrylic cleaners/polishers out there that can be used to restore the acrylic if you do get the paint off. In any case, I suspect it will be cheaper in the long run to just replace the acrylic rather than trying to clean it. 1 Share this post Link to post Share on other sites
Command 97 Posted April 4, 2016 I'd just get a new panel to be honest. I do a lot of 3d printing and plastic work. You can try to smooth up the surface with Methylene Chloride, but over a large surface area, you are literally going to highlight any inconsistency with the backlight. 1 Share this post Link to post Share on other sites
CoachWhite 0 Posted April 4, 2016 I'm sure its Acrylic also. The good side is it's my church that we are doing this for so if I can save them some money that would good. What is your thought on wet sanding with 100 grit? Do you have an idea on a good supplier for new panels? Share this post Link to post Share on other sites
Command 97 Posted April 4, 2016 If you use acrylic/Plexiglas sheets infrequently and don't want to set up with a supplier, Home Depot and Lowes have them available online at the least. Alternatively a vinyl window manufacturer or fabricator in your area may have sheets you can purchase (Some sell odd size remnants for cheap if you don't mind scoring and finishing an edge) 100 grit is a very rough sand. Most wet sanding is done with 400 grit and you still have the issue of inconsistency across the face. Share this post Link to post Share on other sites
CoachWhite 0 Posted April 4, 2016 Thank You Command. Share this post Link to post Share on other sites
Wildgoose 4,200 Posted April 4, 2016 You might work yourself down with sandpaper starting at a rough then gradually finer and finer. I took a nasty gouge out of a motorcycle wind fairing once this way but oh so slow a process. I guess if you are donating your time then it may be worth it (to the church) but you are talking many hours of messing around vs the cost of a new sheet. In the end the cleaned sheet probably won't look as nice either so you end up with a lot of time invested in a bad end result. We call this polishing a turd. Share this post Link to post Share on other sites
Go-C Graphics 856 Posted April 4, 2016 The owners know that we have a 50/50 chance of get the old paint off or buy new panels. My concern for using paint thinner is staining. I read that if you allow Break fluid Dot 3 sit for a while it will remove the paint with little work or having a smearing issue. I'd say you have about a 95% chance of having to replace the acrylic. Anything strong enough to take off the paint will cloud or craze the acrylic. If you wetsand it you're going to have a ton of time involved in polishing it after. Share this post Link to post Share on other sites
CoachWhite 0 Posted April 4, 2016 Thanks for the suggestions guys. I will keep you guys posted. Share this post Link to post Share on other sites
CoachWhite 0 Posted April 5, 2016 FYI break fluid works amazingly for dissolving paint of acrylic signs. I have tried to down load some pics but it won't let me. Share this post Link to post Share on other sites
CoachWhite 0 Posted April 5, 2016 FYI break fluid works amazingly for dissolving paint of acrylic signs. I have tried to down load some pics but it won't let me. Share this post Link to post Share on other sites