Hey gang, While I'm recovering from this dang sciatic junk, I started polishing my weiand valve covers. I ran into an area that looks like a casting defect. It looks like it goes all the way to the inside. I'm wondering if there I something I can put on the inside to prevent oil staining. Maybe JB weld? Thanks, and marry Christmas Full Kustom, drunk mobile posting
I would take a Dremmel tool and enlarge that casting flaw. Take your valve cover to a welding shop and have it aluminum welded. Hand file and finish sand the weld. You can now continue polishing and the welded area will disappear. No more oil leaks and far better than JB Weld.
I would worry about it if it does indeed leak. And JB weld on the inside would probably fix the leak. Getting a clean weld on a casting with a defect like that...hmmm...figure the odds
is it somewhere that can be seen? I think Id tig it, if you have a dremel have a dig, it will need to be Vee'd anyway , maybe JBweld?
First , fill it with water and let it sit to see if it leaks. If it leaks, use JB WELD. TIG welding porous oil filled aluminum can be problematic, even if you first grind it.
If your not going to SEMA or Pebble Beach JB or leave it the hell alone. Sent from my iPad using The H.A.M.B. mobile app
19Fordy is right on the money. That casting is full of oil, and will blow out and fuck up if you weld it... JB is a good idea.
.......... So how do you know the casting is full of oil from looking at a picture? Did you even look at the picture of the valve cover that was posted, and how much oil are you expecting to come gushing out when heat is applied? That casting flaw is quite small and the aluminum looks to be good quality. Whether it is going to be aluminum welded or JB Weld applied a Dremmel will still have to be used to make a V channel and enlarge that casting flaw, and there won't be any oil left once the V channel is made. I have aluminum welded and finished polished to perfection all kinds of vintage aluminum car parts, including flathead Eddie Meyer heads and intakes. The Eddie Meyer stuff is a real challenge. Some people won't even attempt a repair on Eddie Meyer parts. I like to do projects the best I can. If that valve cover was mine I would have it aluminum welded, hand filed, and I would have it polished to a brilliant shine. That valve cover can either be aluminum welded or JB Weld applied. Just depends on what the finished product is expected to be.
My experience was different. Years ago when I did a lot of TIG welding of aluminum, several times I tried to repair cast engine parts, motorcycle cases, cracks, breaks, whatever people brought me to weld. If it was cast, no amount of cleaning would get all the oil out of the casting before welding. A few seconds of welding, a puff of smoke when I'd hit an oil pocket, and then I'd have a dirty hole to repair in addition to the original repair. It wasn't the casting that made it difficult to repair. It was cast engine parts that were exposed to oil that were the problem. I assume that 19Fordy had the same experience that I did. I'm not saying it happened every time, but often enough that it wasn't a surprise when it did.
Porous castings should be baked before welding. It drives most of the ingrained /infused oil out. Doing so greatly increases the probability of success
Yep, Vicky has it exactly right. I weld a lot of aluminum and magnesium castings that have been soaked and baked for years with gear lube. Clean it the best you can with acetone or lacquer thinner. Bake it and then clean it again. Wire brush it shiny with a stainless brush. When actually welding, start puddling well back from the hole. Add filler as needed. Circle the hole and keep working the puddle toward the center. When the puddle bridges the gap, STOP! By doing it this way, you boil off the oil entrapped in the casting before you try to seal it up. Forget about getting a 'row of dimes' bead. If I was going to weld the valve cover in question, I would weld it up from the inside. Then if a low spot was detected on the outer surface, it can be filled with rod. You will probably find that as you weld, it gets easier to work the puddle where you want it. I'm pretty sure that this is due to the heating of the piece. But, I haven't found it beneficial to preheat the whole casting. I think this is because the oil will come out of the pores, vaporize, and contaminate the weld area. Or just JB weld it
My friend just got a new TIG and is taking some classes. After some practice, I might "beer" him into giving it a try, thanks
This... I learned the hard way that any aluminum casting that's had long-term exposure to grease/oil will 'soak' up at least small amounts of it. My experience was with powdercoating; failing to 'pre-bake' the casting would almost guarantee a coating failure or flaw in the finish. Particularly porous castings sometimes would take more than one bake cycle before they quit 'oozing'.... And you don't need to have access to a TIG welder anymore... https://www.aluminumrepair.com/
Aluminum isn't for beginners, especially when soaked with oil. Myself, I'd JB weld it from the back side and call it good. If it leaks in the future maybe worry about it then.
I used to repair aluminum parts for the salvage yard that was next to my shop, long ago. I went through a ton of propane cooking oil out of castings. This is no place for "practice". That's how you ruin good parts.
I've had breather holes welded in a couple valve covers and there can be a difference in the "color" of the aluminum tig rod deposited and the original metal that can become noticeable when polished.
I can tell you that Rich B is right about the color. It WILL show after sanding and polishing. There is NO WAY you can perfectly match the original aluminum. If you don't mind, it won't show a lot. But it will show if you look closely.
I would call this a rare opportunity. Would go out and buy that cobra gas welding outfit and weld that sucker up. Great opportunity to enhance your shop and your skills. I would think it qualify as tax write off if you do it before first of the year!
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