Looking for help with fixing flaws in cast aluminum parts

[progmgr1]

I'm planning on polishing the cast aluminum grill and windshield frame on my '33 and have found a few flaws that I would like to fix, at least cosmetically. For example, there are some small pits in the grill shell and windshield frame that will be more obvious once the parts are polished. Also, there is a gap between the top and bottom halves of the windshield frame, but only on the Driver's side (which means I'll see it every time I sit in the car).

I'm hoping the vast Forum knowledge pool can come up with some product recommendations or suggestions, preferably that don't involve TIG welding.

TIA, Keith HR #894

[J R Jones]

Curious that no one is offering advice. Not having a 33 means I am not experienced on your project but I fabricate. TIGing is one of your solutions, get used to it.
In view of my not seeing your parts I will say (expensive) die cast parts have a smooth surface but porosity inside. If typical porosities come through to the surface you must melt & fill, very difficult.
Sand castings do not have a smooth surface but the castings are dense and easy to TIG.

If your frame has a gap, lengthening it would be very hard. I have seen that on my 1929 Mercedes SSK replica and grinding the glass is the best option to close the gap. I use a belt sander but go easy and keep a wet rag available to cool the glass, MAYBE the frame is not to spec and FFR has one that is a better fit.
jim

[Jacob McCrea]

I can't say I've ever had to fix this sort of thing. But if I did, I might take a fine file and make a pile of aluminum shavings. Then clean the parts with acetone, and fill the holes with clear epoxy. Immediately sprinkle the aluminum shavings onto the epoxy and embed them - much like concrete folks place decorative aggregate on top of a small pad and embed it onto the surface. Let the part dry for a few days, carefully file & wet-sand it smooth and see if it works. Again, I have never tried this but if you don't want to fool around with trying to weld it, I'd give it a shot. I have thought about it and don't have a better idea.

[progmgr1]

Thanks, Jacob. Sounds like an idea worth trying - maybe even mix aluminum powder / filings into the epoxy as a thickener? I might have to do a little experimentation. I've got some scrap parts I could sacrifice to the cause...

Keith HR #894

[Skuzzy]

I have never tried it, but what about using solder to fill the pits? It polishes reasonably well, but it would oxidize faster than the aluminum. Maybe a clear sealer over it? Just thinking out loud.

[progmgr1]

Getting solder to stick to these large aluminum parts would be difficult, since they are a massive heat sink. It might be worth a try if I undercut the pits so the solder would be mechanically held in place.

Thanks for the idea.

Keith HR #894

[Nigel Allen]

https://itwperformancepolymers.com/products/devcon/metal-rebuilding-repair/devcon-aluminum-putty-f

[Skuzzy]

Getting solder to stick to these large aluminum parts would be difficult, since they are a massive heat sink. It might be worth a try if I undercut the pits so the solder would be mechanically held in place.

Thanks for the idea.

Keith HR #894

I think you would need a pinpoint high intensity flame to heat the aluminum quickly in a localized area. Use a low temperature solder wire should help as well.

[progmgr1]

Nigel - Thanks! That Devcon product is exactly what I vaguely had in mind that I needed. Also, it appears to be available from multiple sources in my area or by internet.

Cheers, Keith HR #894

[Skuzzy]

Nigel - Thanks! That Devcon product is exactly what I vaguely had in mind that I needed. Also, it appears to be available from multiple sources in my area or by internet.

Cheers, Keith HR #894

Looking forward to hearing your results with it.

[progmgr1]

After some investigation, I found that the Devcon product was only available in quart or larger containers - priced over $100. Clearly, intended for industrial use. I found something similar on Amazon in a more convenient size and price point: https://www.amazon.com/Star-Brite-Epoxy-Putty-Stick/dp/B001449TTY/ref=pd_rhf_ee_s_pd_crcd_d_sccl_2_3/130-4043910-5591250?pd_rd_w=faYxO&content-id=amzn1.sym.724e1345-13e9-4aaa-ad92-3b2703f86a2c&pf_rd_p=724e1345-13e9-4aaa-ad92-3b2703f86a2c&pf_rd_r=CGEZ8K171KXZGR121PEY&pd_rd_wg=jEU9q&pd_rd_r=7a622a6e-7eca-4026-b8ea-915761264613&pd_rd_i=B001449TTY&th=1

Keith HR #894

[DanQ]

Did you check with Factory Five about this? I also polished my windshield frame and grill (using 1000, 1500, 2000, 2500, 3000 wet, then buff and polish) and they came out looking like a mirror. You paid full price for quality parts and they may be willing to exchange them. My seams on the sides of the windshield are both tight, maybe the metal frame just needs to be tapped down a bit more over the rubber insert. I just looked at my windshield frame gaps and they are tight-you cannot even get a fingernail in them. Post a photo of the gap in the windshield frame please.
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[ggunter]

Sorry, but solder will not stick to aluminum.

[FF33rod]

Did you check with Factory Five about this? I also polished my windshield frame and grill (using 1000, 1500, 2000, 2500, 3000 wet, then buff and polish) and they came out looking like a mirror. You paid full price for quality parts and they may be willing to exchange them. My seams on the sides of the windshield are both tight, maybe the metal frame just needs to be tapped down a bit more over the rubber insert. I just looked at my windshield frame gaps and they are tight-you cannot even get a fingernail in them. Post a photo of the gap in the windshield frame please.
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Most of the castings from FFR have the imperfections that Keith mentions, getting another is extremely unlikely to solve the problem (just like the fiberglass parts). Sounds like some success should be had with the aluminum filler mentioned above but I will say that after polishing mine, you can remove some of the imperfections and you don't really think about the others once you're done....

Steve

Steve

[Skuzzy]

Sorry, but solder will not stick to aluminum.

Never tried it so I was not sure. Thanks.

[progmgr1]

Dan, your grill and windshield frame look fantastic! That's just what I'm aiming for. The one thing I couldn't make out in the photo was if the vertical grill bars are also polished. If so, did you do all that by hand or did you have some Dremel attachments that would fit?

My frame is covered in blue tape right now, so no photo of the gap. However, the problem is caused by FFR using 2 counter-sunk screws on each side to hold the frame halves together. I can close the gap by pressing the halves together, but then they split apart again when I tighten the screws. The tapered hole and angled screw head only allow one assembled orientation of the parts, and that leaves a visible gap between the frame halves. It's driver side only(?) The passenger side fits perfectly.

Keith HR #894