Patching and filling holes in plastic - Page 1
Forum section: electronics / general

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: June 13, 2020, 01:24:47 am
content: So my favorite desktop 8 bitter was never in great shape, I built it from non-functional junk I accumulated over time.The front panel has these terrible drill holes in it.Anyone have a method to fill these and make it as invisible as possible?1- Fill with epoxy and paint over.2- Find a pigment designed to mix with epoxy and fill the holes with colored epoxy,

author: ebastler
author_rank: Super Contributor
timestamp: June 13, 2020, 06:49:12 am
content: You can try with epoxy or something; if I had to close holes like this, I would probably prefer to glue a thin plate (metal or whatever) behind the holes from the inside and use filler. In either case, your only chance of making the holes invisible is to carefully sand and then paint the whole front.But since the original C128 enclosure was never painted to my knowledge, to my mind this would just make matters worse. I would prefer to re-install whatever switches and LEDs were originally mounted in those holes, as a witness of the way we dealt with home computers in the 80s -- hacks and upgrades were common enough among amateurs.

author: Ian.M
author_rank: Super Contributor
timestamp: June 13, 2020, 07:24:58 am
content: Odds are the case is moulded from ABS. To close the holes, plugs made from ABS, either milled out of sheet or 3D printed, with a lip on the interior side, glued in place with solvent (pipe) cement would probably be the best option for strength and long-term stability. Then you need to achieve the best cosmetic result. If the front panel doesn't have a high gloss finish that could be easily over-painted, that may be rather difficult. Worst case, after filling remaining defects, you may have to settle for selectively painting the plugged areas to an acceptable colour match, accepting that they will still be visible and that the colour match will deteriorate as the case colour continues to darken due to aging and ambient UV.

author: cruff
author_rank: Regular Contributor
timestamp: June 13, 2020, 11:38:12 am
content: Do you know about a product called "Plast-aid"? It is a plastic repair kit that consists of plastic powder and a solvent that you mix up to form a moldable lump that you can shape and attach to other plastic to form a repair. The color is certain to not match, but if you had another piece of plastic that color matched the case that you didn't mind destroying and you could grind it into powder, perhaps it would react to the Plast-aid solvent similarly.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: June 13, 2020, 01:09:39 pm
content: Quote from: cruff on June 13, 2020, 11:38:12 amNever heard of it, but they have it here. Will consider it!

author: DrG
author_rank: Super Contributor
timestamp: June 13, 2020, 01:31:33 pm
content: Quote from: cruff on June 13, 2020, 11:38:12 amI did not know about it but it looks pretty cool. I put some on my list.MSDS here:https://cdn.shopify.com/s/files/1/1605/0763/files/SDS_1.2_-_Plast-aid_Repair_Plastic.pdfThe color matching quest is not so easy though. They do offer pigments that can be mixed with the stuffhttps://www.plast-aid.com/products/plast-aid-pigments-plast-aid-coloring-kitand I would think you could get your own pigments elsewhere.This product must have been around for a while because this video looks old:I would very much like to see the final result.

author: themadhippy
author_rank: Super Contributor
timestamp: June 13, 2020, 01:32:40 pm
content: my goto filler for small holes is super glue and baking soda,sets rock hard in seconds,and if your careful you can get it perfectly level without any sanding.