Painting an Aluminium Chassis

[RoadrunnerOZ]

Best to do the lot in etch - try a small section first to make sure it grabs at the junction of bare and coated metal.
The remaining coating may be powder coat - there are strippers designed for that, there are also strippers for 2K.
Do a test first to make sure the primer holds to the remaining paint - if not you’ll need to strip to metal.

 

[scott2000]

Decided to change course and use the paint they had their home's exterior trim done in. Color is a perfect match for the vinyl fence....

Really didn't feel good about putting the extra money into products that had mixed reviews, I'm inexperienced with and didn't have time to waste.

The paint is actually really nice, top tier of Sherwin Williams...Emerald line.... it's zinc fortified with all the anti microbial stuff to combat corrosion and stuff. It's pretty hard stuff when dry plus, touch ups will be a lot easier down the road.... I've worked with plenty of acrylics and they can be very strong and very long lasting if done right. This stuff is actually self priming on bare aluminum...not sure how.... Didn't want to chance that though.

Got the inserts pretty cleaned up..Hit with some 150 to make things nicer...Applied self etching to all of it...not zinc chromate though....

...Sprayed a couple of coats and had water starting to leach out from a couple of the joints.... yuck... Had to deal with that..., sealed the joints with some eurethane modified caulk...sprayed a couple of more coats... I think it'll be fine. The time and money isn't there to worry about it but, I feel pretty good ..... The original finish didn't last but not even 7 months..... This should be an easy 7 years.... but mother nature may be snickering...

Paint was super thick and I didn't want to mess with thinning ...Had to use a big tip and it turned out like a rock finish almost... Kinda cool.. Not normally what you'd want but most of their outdoor furniture has same texture...Maybe powder coat....

We'll see. Lot of coating on them now....Got some 316 bolts for everything... $75 just in those.... probably going to put some neoprene washers under them just to give a little extra for water to deal with....

Thanks so much for all the info. Fascinating stuff and I was actually able to relay info to the guy that made these inserts so he doesn't do that again..

 

[RoadrunnerOZ]

Cool stuff - good to hear. Looks good

 

[scott2000]

Thanks... are you familiar with Kynar coatings? PVDF
https://industrial.sherwin-williams...rusion/products-by-industry/all-products.html

 

[RoadrunnerOZ]

Dangerous process as it requires Chromate chrome-based conversion coating before priming and painting. It’s not a good DIY project process as far as I can see.

 

[Gold]

I finally found the time and worked up the courage to start painting the project boxes for my phono preamp front end.

 

[RoadrunnerOZ]

I finally found the time and worked up the courage to start painting the project boxes for my phono preamp front end.

Looks like a bit of overspray on your floor looks good

 

[RoadrunnerOZ]

Or is it a bench? Boxes look good.

 

[Gold]

It’s a bench. I didn’t have a deeper box. I can and do sand the butcher block a few times a year.

 

[RoadrunnerOZ]

I made myself a spray box with side and front plastic skirt coming out from under the box so I can do it without too much overspray - the top of the box I cut a hole at the back and put on my filter box from the airbrush spray box I made.

 

[scott2000]

What makes that particular primer self etch? Was looking at the Seymour stuff before... Not all self etches are corrosion resistant or is there something in there that does that? Or is self etch different for different purposes?
https://cdn.amplifi.pattern.com/d55ba6d0-2278-4df4-8bbc-26f7678932e2
here's the gray
https://cdn.amplifi.pattern.com/bed6c864-072b-4251-93f1-3d3c115543ee
edit...I see at the bottom there is zinc phosphate mentioned.... unclear what that section is...

 

[RoadrunnerOZ]

It is zinc rich - some form of zinc salt (like zinc oxide and zinc phosphate) which bonds to the metal leaving zinc - some primers are designed for just bare steel/iron others for aluminium as well as ferrous metals - the one you have is suitable for auto body bare metal and aluminium. Some primers also include corrosion inhibiting pigments (as there are many based on metal salts which give them their colour). Some primers are weld-through as well. I’ve always just used the auto primers as they are suitable for both types of metal and come from the suppliers in bulk liquid or spray cans.

 

[scott2000]

Came across this company the other day...this stuff looks interesting
https://bilthamber.com/product/electrox/
but says steel....

 

[RoadrunnerOZ]

I think the zinc phosphate bonds to steel (and zinc chromate bonds to aluminium) but some primers use an acid salt which when reacted with the aluminium oxide layer allows polymers in the paint to bond to the metal. Most etch primers need to be thin layered or will delaminate from the paint topcoat.

Came across this company the other day...this stuff looks interesting
https://bilthamber.com/product/electrox/
but says steel....

Steel only - much the same as other ferrous metal primers but is a sort of cold galvanising coating by the look.

 

[RoadrunnerOZ]

I think the zinc phosphate bonds to steel (and zinc chromate bonds to aluminium) but some primers use an acid salt which when reacted with the aluminium oxide layer allows polymers in the paint to bond to the metal. Most etch primers need to be thin layered or will delaminate from the paint topcoat.

Steel only - much the same as other ferrous metal primers but is a sort of cold galvanising coating by the look.

What makes that particular primer self etch? Was looking at the Seymour stuff before... Not all self etches are corrosion resistant or is there something in there that does that? Or is self etch different for different purposes?
https://cdn.amplifi.pattern.com/d55ba6d0-2278-4df4-8bbc-26f7678932e2
here's the gray
https://cdn.amplifi.pattern.com/bed6c864-072b-4251-93f1-3d3c115543ee
edit...I see at the bottom there is zinc phosphate mentioned.... unclear what that section is...

Not sure what etches/bonds to the aluminium - as this is a hazardous materials and toxicity sheet and not an ingredients list. There may be a component salt that reacts with the aluminium oxide layer converting it to something that bonds to another ingredient.

 

[Gold]

I made myself a spray box with side and front plastic skirt coming out from under the box so I can do it without too much overspray - the top of the box I cut a hole at the back and put on my filter box from the airbrush spray box I made.

This is a first attempt. I wanted to see how much it stinks. I think I can come up with something that can be open for spraying and then closed and vented through a filter.

 

[RoadrunnerOZ]

This is a first attempt. I wanted to see how much it stinks. I think I can come up with something that can be open for spraying and then closed and vented through a filter.

It does stink doesn’t it! I got sick of using dropsheets all the time as they are really thin and blow around so I used thicker plastic - heavy concrete form plastic sheet you buy by the meter or roll. It’s the 200uM thick stuff taped to the outside of the box so I can just chuck it once it’s starting to get too built up and shedding paint flakes. I also opened the sides of the box to give it angled wings to get the spray nearer the job. It’s easy to get replacement boxes here.

 

[Gold]

I have to have something that packs flat. I have no room for anything. I figure a wood box that can be screwed together in a minute or two. After spraying, close up the front. The front would have an air inlet filter. Have an outlet hose on top. Then a charcoal filter followed by an exhaust fan.

 

[RoadrunnerOZ]

You can always use hinges on a wooden box - you just need to step the sides and bottom staggering one timber thickness extensions each piece to get a flat fold against the back, top no stagger, side 1 stagger 1 thickness, side 2 - 2 thicknesses, base 3 thicknesses - these extensions are screwed to the back-plate in line with the piece they’re extending and then the hinges. Bit of woodwork and 8 hinges and 2 shelf supports (like they use in wardrobes with adjustable shelf height). Base needs to be wider for the sides to rest on so it doesn’t fall inwards, to support the top use the shelf supports that plug into holes in the top front of each side.
Or if you can get removable pin hinges you don’t need to do extensions.

 

[Gold]

I was thinking more along the lines of cutting aluminum L stock into a bunch of brackets. Then use wood screws to use the brackets to make the box. It could come completely apart and pack flat. It would be easy to replace anything.