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Post by mozza on Jun 30, 2015 10:45:11 GMT
I'm still collecting parts for the Slabby rebuild. I have a few (read ALL) panels that need repairing. Is it worth going down the soldering iron route? I have an original donor panel I could use for 'filler'. Or, is it better to go for a plastic repair kit? Someone on here was advocating the virtues of 'Plastex'. Is it any good for our use? Has anyone else used it, or an alternative? Bear in mind, the repair has got to be reliabe, as I don't want cracks appearing after an expensive respray!
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Post by p4ddy on Jun 30, 2015 11:06:31 GMT
On mine I used cable ties to melt and join 2 half's together then a small amount of fibre glass repair for extra strength as my nose cone was snapped in a high stress point. So far it's held but without the fibre glass on the back it kept cracking after a few weeks. I sanded down the fibre glass then blew over the whole thing in red paint. I'm happy with the result so far but I'll wait a couple of years to see if it's still holding good before I respray the bike.
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fallenangels
Oviraptor
Posts: 5 
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Post by fallenangels on Jul 1, 2015 5:52:16 GMT
I would always plastic weld...you takea dremel with a pointy bit to drill a wedge down the crack of the line on both sides, then you heat an ABS plastic rod down the middle until it melts the two parts together like welding metal...never had a problem out of it if done on both sides.
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Post by wsn03 on Jul 1, 2015 9:49:48 GMT
I had a little play with JB WELD - unbelievable results - you must bond the break, then spread it like filler to encase the problem area. Dead strong, been using it on a Yamaha I've been restoring.
I use Duck Tape to hold the pieces in place.
Curing time is a good 3 or 4 days.
Rub down with very coarse sand paper, then switch to wet and dry.
I've since found others saying it is the fix to use.
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Post by p4ddy on Jul 1, 2015 11:50:29 GMT
How does this hold out on high stress areas Under constant pressure?
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Post by wsn03 on Jul 1, 2015 12:20:08 GMT
How does this hold out on high stress areas Under constant pressure? I don't know. I do know that it is designed for metal repairs in place of welding, ive heard of it used for sump. and even head repairs. It is strong but not flexible. ...Ive read others using it for fairings. Ive just used it for a hand blister that was broken in 5 pieces with a chunk missing. |
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Post by p4ddy on Jul 1, 2015 12:45:54 GMT
I'm thinking of trying to repair the broken exhaust ports on my old head I'm going to refit.
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Post by zooma on Jul 1, 2015 13:08:42 GMT
I'm thinking of trying to repair the broken exhaust ports on my old head I'm going to refit. Can't vouch for this stuff as I've never usd it before meself... but it has been around for a long time. Do some research online and see what ya think  lumiweld |
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Post by p4ddy on Jul 1, 2015 13:46:40 GMT
Not sure that would work for me as I don't have the broken bits to weld back on. That's why I'm considering jb-weld as I can use a good amount to make up the gap.
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Post by arnout on Jul 1, 2015 15:26:16 GMT
The succes of plastic welding depends largely on the type of plastic the fairing is made from.. The cream coloured thin type of plastic (scientific name ) panels often found on Suzukis is rather brittle and will dissolve rather than melt with heat.. It can be welded but the welded seams are very weak.. The black coloured thicker type of plastic sadly not often found on Suzukis can be welded very nicely, and the seams will be as strong as the original material.. Here's the muddy on my Kat I welded together from 2 different parts.. (doesn't look pretty here yet, but is very strong)  So.. If you're not sure what kind of plastic you've got just try welding 2 bits together in a hidden spot.. If it turns out the weld is brittle, the only option left is to use (pref. epoxy plastic) glue to stick the broken bits back together.. Use plenty of glue on the inside of the panel, and reinforcing the join by sticking some sort of fine steel mesh over it (and soaking it in glue) will improve the strength a lot.. Can't vouch for this stuff as I've never usd it before meself... but it has been around for a long time. Do some research online and see what ya think lumiweldAh.. I used the stuff sold under the durafix/easyweld name, which is probably the same stuff.. It is great but does require a learning curve.. Especially useful for "welding" smaller aluminium parts together that would otherwise just melt straightaway with TIG/MIG..  The hard part of this proces though it getting enough heat into the workpieces so they are hot enough to melt the solder.. This is very difficult with larger parts like cylinders/heads etc unless you have a really big propane torch as the heat escapes/spread quickly with aluminium.. Also the required heat (390 deg. C) might be too much for installed parts (seals, gaskets) in the head anyway.. |
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Post by zooma on Jul 1, 2015 17:09:52 GMT
Not sure that would work for me as I don't have the broken bits to weld back on. That's why I'm considering jb-weld as I can use a good amount to make up the gap. Got any pics showin' those damaged ports?. I'm sure if you ask slabby Dave nicely, he'll let you go round his place and break a few bits off his engine with an hammer  Ah.. I used the stuff sold under the durafix/easyweld name, which is probably the same stuff.. It is great but does require a learning curve.. Especially useful for "welding" smaller aluminium parts together that would otherwise just melt straightaway with TIG/MIG.. The hard part of this proces though it getting enough heat into the workpieces so they are hot enough to melt the solder.. This is very difficult with larger parts like cylinders/heads etc unless you have a really big propane torch as the heat escapes/spread quickly with aluminium.. Also the required heat (390 deg. C) might be too much for installed parts (seals, gaskets) in the head anyway.. Thanks for those tips and advice fella.... lumiweld/durafix e.t.c is just one of many products I know about, have never used, but imagine I will one day |
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Post by p4ddy on Jul 1, 2015 17:48:06 GMT
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Post by zooma on Jul 1, 2015 18:09:15 GMT
Can't find a definitive answer to the heat generated around the headers on these engines. I suspect that the 550 degrees fahrenheit JB weld is rated to, may be an issue?. No expert on this but if it were me, I'd be looking at having those missing pieces replaced... either by usin' some cast ally bits taken from a seriously buggered motor or seeing if someone could cut somethin' to fit and then have 'em weld it in place. Didn't spend long enough on the welding course I did to know if it's even possible to weld regular ally to cast.. but it may be, and if so it wouldn't be that hard to put a new piece in. Only other thing I can think of is the few Brit bike restorers who repair broken cooling fins.. have a google mate and see what you can turn up. |
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Post by zooma on Jul 1, 2015 18:27:33 GMT
You might find this interestin' Broken FinsSeems like lumiweld is a good idea for fins but not so for anything near the exhaust ports... so, if that stuff can't take the heat, very much doubt JB weld will. That just leaves gettin' an ally welder to put some new pieces in or a new head. |
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Post by badgerkdd on Jul 3, 2015 19:43:14 GMT
For plastic repairs I use a few different methods, but a simple and inexpensive method of reinforcing cracks in panels is to key sand the reverse of the area ( most important part, usually missed ), get a scrap of fibreglass WOVEN cloth ( not chop strand ), place it into position bridging the crack, then pour a liberal amount of SUPERGLUE over the cloth. WEARING DISPOSABLE GLOVES rub the glue into the cloth making sure its well pressed into the plastic surrounding the crack, leave it for an hour or so and your good to go!
If you are able to get hold of Epoxy resin thats the best stuff to use, but it is very expensive. A trick boat builders use, normally to bond fibreglass to metal, is to wet and dry sand the bonding area ( 240/ 320 grit) using catalysed resin first. While the resin is still curing ( e.g. not gelled ) laminate any patches to the area before leaving overnight in a warm ( 24 DegC + ) place. The act of wet and drying with the resin means you physically mix your resin and substrate giving a strong bond.
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