TOPIC: Repairing aluminum castings

One of the cove castings on my Glastron has a crack at the tip near one of the screw holes. Looks like it got bent and stared to fail. It is still connected and useable, but I would like to do something to strengthen it.

The casting is unique to 59 Glastron and maybe to this model, so the likelihood of finding a replacement is remote. Also, having a new one made is way beyond budget.

Thoughts?

JB WELD ??

woosterken

Thought about that but am a little unsure about welding 52 year old aluminum (brittle? alloy issues? etc). Also have thought about aluminum epoxy such as Hy Bond. The casting will have minimal load, but will be bouncing around on the water (someday) Don't want the piece to fail and loose the tip.

jb weld is like bondo, not welding with heat

woosterken

Is it possible to make a wax coppie and try to pour a new aluminum casting with a replaced wax method? I am hoping to try this this spring when I have the sap boiler running good and hot and am done with or before I do a batch of syurup...

Is there a reason you don't weld it or get it welded?

todd,harbor freight has low temp aluminum welding rods you can use with a propane torch,it "might" be an option,john p.s. i guess a should have said brazing

I've never done any welding and this is not the piece to learn on. I will leave that to the experts. My concern on that was if there would be a problem due to the casting's age.

Age won't hurt unless it's corroded badly and causes welding problems. The real concern is to find metal for the filler rod that won't look different. The best case would be to find another junk casting of the same mix from another similar boat, then cut it up for filler rod. Then you'll be using the same metal and after filing the weld down and polishing it will not show. A generic rod off the shelf might have a different color to it.

stashm2,
check this out .... www.freemansupply.com

they have videos how to make casting molds and all the supplies.

could you use a soldering gun then there is as much heat?

woosterken

thetudor wrote:

One of the cove castings on my Glastron has a crack at the tip near one of the screw holes. Looks like it got bent and stared to fail. It is still connected and useable, but I would like to do something to strengthen it.

The casting is unique to 59 Glastron and maybe to this model, so the likelihood of finding a replacement is remote. Also, having a new one made is way beyond budget.

Thoughts?

I have a similar (worse) problem on a couple of castings for my Glaspar G3. I plan to have them recast. One solution I had considered was to back up the failed piece with a thin strip of ??? SS? Aluminum? Brass? either soldered (or brazed, or welded) in place or mechanically fastened. The problem being, of course, that you'd have to recess the hull for the added thickness.

Another potential solution was to cut away past the failed part to where there was good material and weld in a shaped piece to replace the bad part. Not practical for my G3 pieces because they're so thin.

I expect they'll cost somewhere in the neighborhood of thirty bucks each when I get around to having them recast.

If you can, post a picture so we can get a better idea.

Are the parts aluminum or something else that's been plated?

Here's a pic of the problem area plus a full shot of the casting. Thanks for all of the great suggestions so far. Keep em coming.

Afternoon Guys,

Just an idea on your castings. Do any of the junior or senior high school shop or Vo-Tech programs around you teach sand casting? I have seen some very good sand castings come outof those programs. In a lot of cases, the instructor will help you out for the cost of materials.

With the knowledge you guys have, you may even be able to cut a deal to be a visiting instructor for a day or so and talk about the terrific work you've been doing on boats. That may be the key to some Saturday workshops at the school for dads and sons - more people interesting in our hobby.

These are just a couple of ideas I had that I thought might be feasible. Take care.

It appears the crack is on the back and might be able to be welded on the back without it affecting the front. My concern is it's pretty pitted and might not be any good when it's done. You'd have to sand through the pits, then polish.

In my opinion, the crack is a minor problem. Most anyone at all skilled with a tig could fix that.

Then again, the picture may be misleading and it may not be as pitted as it looks.

But, as far as the crack, if it isn't coming through the front it could be welded with any rod and not show, even if it is through it wouldn't make much difference.

Most of the trade schools around here are for machinists. That's where the demand is. Did not find anything for casting. Even RI didn't have anything for casting

The pitting on the casting is relatively minor. I did start on a section of it and it should polish up well. In a perfect world, it would be nice to have them re-cast because there are some scrapes that will not come out. However, I am going to be spending a lot on other items so I need to keep the cost under control. Perhaps in the future I would do it as Phase II of the restoration (unless I get a good deal on it now).

The crack does go to the front, but not as far. I haven't cleaned off the back of the casting, where the photo shows, because I wanted to see what I am going to have to do first.

If I could get new castings for $30 a piece, I would jump on it. It would take me a lot more than $60 to set something up to do it myself.

Looks like it could be soldered easy, Heat with MAPP gas, flux a couple times and flow fill with solder. If ya let it go chances are it would continue to crack. Might be able to pack the crack with JB Weld using a dental tool.

Do any of the machine courses involve a CNC machine? That would give you a very accurate copy. I've seen parts scanned in and alterations done to them to cover breaks, etc. The CNC then makes a new version beter than the original from any material you like. Might be work checking into.

Todd, nice info on the CNC machine. That's out of my knowledge base. There is a technical HS that offers a CNC program not far from me. Will check into it.

I can't remember the propane torched aluminum 'soldier' or 'brazing' product Jasoutside used on his Islander rebuild @ Ib@ots, whether he finished the work or not & if he had good results. He was filling in a mitered joint on his aluminum trim & it was already installed. It's probably similar to one of the products mentioned above & all of the posted ideas sound like good possibilities.

I haven't found a caster/CNC machinist to tackle my cleat problem yet either. It is now sitting on my desk at work so I see it all day.

Have a great holiday season this year!

JC

Any competent welder can repair that casting in a jiffy. Ask to see a sample of the welder's work, or get a referral to someone who knows what they are doing. A difference in welding rod color will be very difficult to see on a contoured part like this. The age of the casting is not a problem. Have the screw hole completely filled, and damaged areas ground out & welded. No big deal. Re drill the part for the mounting screw & counter sink the hole for an oval herad screw. Clean it up with a disc sandner and finish sand by hand. Then buff it out & it'll look like new. I have stuff welded all the time - Aluminum is VERY forgiving.

The "Home brazing" stuff is called Durafix. It works OK, but it is not aluminum. It's a zinc alloy of some sort. The part has to be perfectly clean or the rod won't adhere. A small part like that casting could become overheated & melt if not very careful. Also, the durafix metal is much harder than the parent aluminum, and re-shaping the part after brazing with Durafix is very tricky because if this. I use Durafix on some stuff & it works great. But on this part, I would leave this work up to a professional welder.

my father in law,a retired welder at a power plant,told me a little trick that they would do to aluminum.
basically they would take an aluminum wire(kind of like you have for entrance cable to a house)then heat it just a little then dip it in boraxo soap(the soap cleans out any impurity s and acts as a flux)then heat it up and fill the crack or hole.

i havent done it personally but i think it would work if you can find boraxo soap,lol,john

Have you thought of using silver solder to repair the crack? Pretty easy to use with a propane torch.

Sand casting is what I did to recreate some G3 corner trim. It was very inexpensive, I had two aluminum pieces done for $32 ($16 each). The problem is that on a detailed piece, the surface comes back rough from the sand cast process and needs to be sanded and polished. Creative Castings in Tacoma, WA is who I used... great guys.