dannyboy Posted November 30, 2015 Report Share Posted November 30, 2015 Wondering if anyone had any advice. Just picked up a Defender 90 as a project to get ready for next shooting season. Annoyingly, previously it had a roll cage fitted to it, which means there are holes drilled in the rear tub. To avoid getting a whole new tub, a friend recommended using some fibreglass paste on the underside to fill the holes, sand that down and then putting some filler over on the top side and sanding that down flush. Just wondering if anyone had done anything like this or saw any potential issues with this, as I will be spending £1500 on a respray. Don't want to run into any issues down the line. Cheers! Quote Link to comment Share on other sites More sharing options...
ditchman Posted November 30, 2015 Report Share Posted November 30, 2015 Square off the holes ...........then rivet a plate over them........ Quote Link to comment Share on other sites More sharing options...
oldypigeonpopper Posted November 30, 2015 Report Share Posted November 30, 2015 hello, not knowing what the tub is and what size holes i would be more inclined to find a flat plastic insert for the holes and then a little filler on top sanded down or if you can get to the back and does not show some fibreglass cloth glued with filler on outside and then your respray. Quote Link to comment Share on other sites More sharing options...
oldypigeonpopper Posted November 30, 2015 Report Share Posted November 30, 2015 hello, not knowing what the tub is and what size holes i would be more inclined to find a flat plastic insert for the holes and then a little filler on top sanded down or if you can get to the back and does not show some fibreglass cloth glued with filler on outside and then your respray. or get some one to mig weld a plate over Quote Link to comment Share on other sites More sharing options...
Big Mat Posted November 30, 2015 Report Share Posted November 30, 2015 or get some one to mig weld a plate over Tig weld, body is Ali Quote Link to comment Share on other sites More sharing options...
ditchman Posted November 30, 2015 Report Share Posted November 30, 2015 (edited) use MAPP Gas...and laser brand rods......and smear some soap on it ...when it turns brown it is hot enough to braise with alli/composite rod... Edited November 30, 2015 by ditchman Quote Link to comment Share on other sites More sharing options...
rodp Posted November 30, 2015 Report Share Posted November 30, 2015 Where in the tub ? If it's the floor where the backstays went through to chassis then rivet a plate underneath the holes and bed liner the rear tub. If they go through the sides (outside) then tig welding is the answer, but they'll never go perfectly flat. use MAPP Gas...and laser brand rods... There's very few folk who can gas weld ally nowadays. I haven't done it for donkeys years, tig killed it off. Quote Link to comment Share on other sites More sharing options...
ditchman Posted November 30, 2015 Report Share Posted November 30, 2015 (edited) Where in the tub ? If it's the floor where the backstays went through to chassis then rivet a plate underneath the holes and bed liner the rear tub. If they go through the sides (outside) then tig welding is the answer, but they'll never go perfectly flat. There's very few folk who can gas weld ally nowadays. I haven't done it for donkeys years, tig killed it off. GOOGLE....laser brand alliminuin welding and you will see what i mean....watch the short video Edited November 30, 2015 by ditchman Quote Link to comment Share on other sites More sharing options...
rodp Posted November 30, 2015 Report Share Posted November 30, 2015 Think I tried a similar thing years ago, snap on used to sell them. I didn't have much success to be honest, couldn't get them to flow or penetrate. Quote Link to comment Share on other sites More sharing options...
ditchman Posted November 30, 2015 Report Share Posted November 30, 2015 Think I tried a similar thing years ago, snap on used to sell them. I didn't have much success to be honest, couldn't get them to flow or penetrate. the trick is to "tin" the area first with a s/s brush....then its easy.. Quote Link to comment Share on other sites More sharing options...
rodp Posted November 30, 2015 Report Share Posted November 30, 2015 Tried everything, but no good. Mind you, it was probably 20 odd years ago so they'll have improved by now. Got a tig now though so doesn't matter :lol: Quote Link to comment Share on other sites More sharing options...
oldypigeonpopper Posted November 30, 2015 Report Share Posted November 30, 2015 Tig weld, body is Ali hello, sorry i did not know yes TIG would be another way to go. Quote Link to comment Share on other sites More sharing options...
dannyboy Posted November 30, 2015 Author Report Share Posted November 30, 2015 So, the consensus is to TIG weld the holes. They are on the outside, four holes on each side probably 5mm Would this create a smooth enough finish for painting ? or would I best to keep an eye out for a decent tub from a breakers... Quote Link to comment Share on other sites More sharing options...
rodp Posted November 30, 2015 Report Share Posted November 30, 2015 So, the consensus is to TIG weld the holes. They are on the outside, four holes on each side probably 5mm Would this create a smooth enough finish for painting ? or would I best to keep an eye out for a decent tub from a breakers... 5mm, small cage ? Wouldn't bother tigging. Clean inside spotless and stick plate on inside with sikaflex adhesive sealant, or similar from body repair supplies shop. Then fill over and flat. Put a decent size ally plate inside, about 2" or 3" square. That stuff sticks like .................. well, you know what. Or you could get them tigged then GENTLY panel beat flat, but if you stretch the ally it's all over Got to ask though, why the trouble on a defender ? Just pop some large head rivets through them, or pan head bolts if you don't have a gun big enough. Quote Link to comment Share on other sites More sharing options...
B391 Posted November 30, 2015 Report Share Posted November 30, 2015 either rubber gromets or rivet ali sheet with mastic under the edges Quote Link to comment Share on other sites More sharing options...
Xr1200 Posted November 30, 2015 Report Share Posted November 30, 2015 Be careful when tig welding make sure you get some one who knows what their doing otherwise you could end up with a larger hole ive been welding aluminium for years and when it's old it gets a porous layer on it and it can quite easily blow back and you end up with a right mess which is very difficult to weld Quote Link to comment Share on other sites More sharing options...
coldweld Posted November 30, 2015 Report Share Posted November 30, 2015 Id be more worried about the Chassis, If it's had a roll cage it proberbly been in some Pay N' Play areas and filled the chassis with mud that then holds moisture. Quote Link to comment Share on other sites More sharing options...
Lord Geordie Posted December 1, 2015 Report Share Posted December 1, 2015 There is a method of welding using just a blow lamp! Forget the name of it! But if you can solder, then you can weld! The videos online are great and it can be used for building up alloy castings and welding aluminium together. Quote Link to comment Share on other sites More sharing options...
deershooter Posted December 1, 2015 Report Share Posted December 1, 2015 Why don't you gust put bolts in the holes job sorted Deershooter Quote Link to comment Share on other sites More sharing options...
ferguson_tom Posted December 1, 2015 Report Share Posted December 1, 2015 From the little bodywork experience I have I would do the small plate from behind then a filler from the top and smooth flat. I would use the silkaflex you find in caravan shops, it is unbelievable how strong it is. I have used the fiberglass stuff before as well and it works well but is messy. Quote Link to comment Share on other sites More sharing options...
dannyboy Posted December 1, 2015 Author Report Share Posted December 1, 2015 (edited) Cheers for all the advice on this one. I think I will go for the plate behind and fill in the hole. That should do the job. Job would be too tedious to tig weld, and with the panel being Ali could go wrong 5mm, small cage ? Wouldn't bother tigging. Clean inside spotless and stick plate on inside with sikaflex adhesive sealant, or similar from body repair supplies shop. Then fill over and flat. Put a decent size ally plate inside, about 2" or 3" square. That stuff sticks like .................. well, you know what. Or you could get them tigged then GENTLY panel beat flat, but if you stretch the ally it's all over Got to ask though, why the trouble on a defender ? Just pop some large head rivets through them, or pan head bolts if you don't have a gun big enough. Yeh maybe more like 12mm lol It is a really tidy defender otherwise last of the Td5's, that I got at a crazy low price at a company auction (£1.5k), so worth the hassle as the end result will be good. Id be more worried about the Chassis, If it's had a roll cage it proberbly been in some Pay N' Play areas and filled the chassis with mud that then holds moisture. The roll cage was fitted for safety as it was a works vehicle, in a mining type company. So it's life hasn't been too bad, run up 80k on the clock.I'm going to pressure wash and steam clean the chassis inside and out, before applying wax oyl Edited December 1, 2015 by dannyboy Quote Link to comment Share on other sites More sharing options...
bumpy22 Posted December 1, 2015 Report Share Posted December 1, 2015 get a decent 2 pack bond . put the plate underside and sand the excess bond around the hole. most bonds are sandable and makes filling pointless. i would not attempt welding as it will make a simple job into a large one Quote Link to comment Share on other sites More sharing options...
coldweld Posted December 1, 2015 Report Share Posted December 1, 2015 Don't rush washing the chassis inside and out, then use a needle gun and finish with a Dinitrol kit waxoil is not as good Quote Link to comment Share on other sites More sharing options...
dannyboy Posted December 1, 2015 Author Report Share Posted December 1, 2015 People suggested using sikaflex as the bonding agent, I am assuming I could let this stick the plate down and fill the holes, then sanding down the excess. Meaning there wouldn't be a need for a filler. A few videos I have watched do this for decking of boats. The other thing I have come across is this Durafix rod. You heat the surrounding area up to 720 degrees and then almost solder the rod on to fill the hole. Then I assume I could grind and sand this down smooth enough to paint. In this video (really cheesy american) He fills in a hole almost exactly like the ones drilled in the body work. Thoughts ? Quote Link to comment Share on other sites More sharing options...
amateur Posted December 2, 2015 Report Share Posted December 2, 2015 (edited) This is the the same method as Ditchman gave you in post 6 above - using a propane or (better) MAPP torch and high zinc content aluminium rods. These come in a variety of trade names - Laser, Lumiweld, Technoweld, HTS 2000 as well as Durafix and can be bought cheaply on Ebay As long as the aluminium is scrupulously clean and well scraped with the stainless steel brush supplied, the hole-filling technique as shown on the video should work, and you don't run the risk of distorting the aluminium panel because the temperatures are lower than TIG welding. The downside is that the material itself is a darker colour than aluminium, so won't match your panel and it is harder than aluminium, so more difficult to sand down. That said I have used Lumiweld to fill in holes in bike castings, repaired stripped threads and fabricated bits and pieces out of thin-gauge aluminium. It really is as easy as soldering and relatively cheap. Edited December 2, 2015 by amateur Quote Link to comment Share on other sites More sharing options...
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