Dip Coating

[cprobertson1]

I am currently building a cheap and cheerful aluminium frame to protect my ham radio rig when I go portable with it - and I've decided that instead of having it powder coated or spray-painted - I want to coat the whole thing in plastic or rubber.

I also have a number of other things I can use the dipped plastic coatings for - in particular damaged tool handles, strain relief for wires and coatings for certain handheld enclosures.

A quick glance has suggested that "plastidip" would suffice for these purposes - but the tins are pretty small and expensive to boot!

I've seen several other liquid-rubber style paints like Ronseal and even had a glance over liquid latex (for mould-making) but I'm not sure these would stick suitable to the (primed) aluminium.

Has anybody got any suggestions on what I can use for dip-coating things?

NB the aluminium frame is made from 6mm aluminium round bar and is 300mm x 120mm - meaning I'd need enough dip-coating to cover the whole thing (or a spray-on coating)

--EDIT--
Underbody sealants might do the trick: usually made of bitumastic rubber, flexible, doesn't crack, decent metal adhesion. Anybody have any experience with this?

[Benta]

Underbody sealants might do the trick: usually made of bitumastic rubber, flexible, doesn't crack, decent metal adhesion. Anybody have any experience with this?

My experience is that it is very sticky and stays that way...

[DTJ]

Yeah, underbody sealant is not suited. It can stay tacky and makes your hands grubby.

[macboy]

Look at spray-on truck bed liner stuff. This dries to a very durable plastic, but still not super hard (or it would crack and chip too easily). Maybe a company that does these would do your frame for a reasonable price. You can also buy that by the gallon, quart, or spray can. I found one called "EZ Liner" which is refer to as "Bedliner and Industrial Strength Coating". About $11 Canadian pesos for a 467g spray can.

[Ian.M]

If you want it to stand up to abuse, you'll need to prime the aluminium with an etch wash primer, and may still need a tie coat of something like a hard polyurethane before applying the bedliner. 

[drussell]

+1 for truck box spray liner.

When I first bought my truck back in '98 I had the dealer have Line-X spray in a box liner when it arrived to the dealer from the factory.  I thought it might get scratched and require touch-ups eventually but the first time I put some real stress on it I realized how tough the stuff really is.  I slid my engine hoist shop crane into the back of the truck and it didn't scratch the liner at all, rather it scraped the paint off the steel hoist. 

That good stuff is TOUGH!!

The professional shop stuff is much better than what you get in a can at the parts store and the coating shops will happily coat other items than truck boxes for you.  People do it all the time with road cases, P.A. speaker enclosures, etc.

[cprobertson1]

Huh... I could have SWORN I had already replied to this... Strange!

+1 for truck box spray liner.
......
That good stuff is TOUGH!!

The professional shop stuff is much better than what you get in a can at the parts store and the coating shops will happily coat other items than truck boxes for you.  People do it all the time with road cases, P.A. speaker enclosures, etc.

Aye, I think that will be the way to go!

How flexible is it? For instance, if the underlying aluminium is bent or flexed, will it crack and flake off?

If you want it to stand up to abuse, you'll need to prime the aluminium with an etch wash primer, and may still need a tie coat of something like a hard polyurethane before applying the bedliner. 

I'll speak to the local car shops later today and see if they'll do proper priming/tie coat as part of their application process and see what they say - worst case scenario I'll shot-blast the aluminium and get it primed.

Yeah, underbody sealant is not suited. It can stay tacky and makes your hands grubby.

You bet me to it! I actually figured that one out myself: I got the magical idea of visiting a local autorepair shop and explained that I was considering coating something in the sealant and wanted to get a quick look at what it was like when freshly applied/dried.

Apparently there are two variants of it - air-dry kind and uv-cured: air-dried tends to have a tacky feel to it and the uv-cured stuff (which they didn't have in the shop, they only buy it in when they need it) has an oilier feel to it - but both will pick up crap and wouldn't be good for coating a frame

I wish I had mentioned what I planned on coating to them - they might actually have suggested the truck-box spray-liner themselves!

Oh well - will let you know how it turns out.

[cjdubea]

I'm in the ROV business.  https://en.wikipedia.org/wiki/Remotely_operated_underwater_vehicle

We pot all our electrical splices in ScotchCast 2136.  Waterproof down to 5000 meters. Don't see why you couldn't use it to pot a board. You can get it from Amron https://www.amronintl.com/catalogsearch/result/?cat=0&q=scotchcast

Oh, and once it's potted, there is no getting the stuff off....