The BSA A7-A10 Forum
Bikes, Pictures, Stories & more => Wanted & For Sale => Topic started by: route 66 on 15.03. 2023 09:44
-
Does anyone have any scrap barrels that I could use for pieces of fins to repair mine? Any help appreciated
-
swap meet or local buy and sell might be your best bet as its a heavy item to ship .
-
Hi All,
I got a couple of Bantam barrels as fin donors, they have good deep fins so lots of material in them
A lot cheaper than A series to post as well
John
-
Or you could shape the fins from mild steel & weld on.......
-
Thanks guys,I got a barrel from a bantam for £15,job done
-
Or you could shape the fins from mild steel & weld on.......
How did you go with the welding Orabanda, did you preheat the cast iron barrel first also interested to know what rods you used if MMA welding or did you use MIG? I've got an A7 barrel with a few fins missing...
-
BagoNails,
Yes; preheat required.
Used the rods recommended by BOC (not cheap).
Successful repair recently of A& LS head; will dig up the pics.
-
BagoNails,
Yes; preheat required.
Used the rods recommended by BOC (not cheap).
Successful repair recently of A& LS head; will dig up the pics.
.
Ni rod is for cast iron it can also be brazed or silver soldered pre heat , chamfer edges to be joined and let everything cool slowly together……. Likely lots of vids on u tube
-
I repaired a set of barrels some time ago using milds steel plate, stitch welded with a mig. I have done quite a few fin repairs like this now and all have worked out well.
-
I repaired a set of barrels some time ago using milds steel plate, stitch welded with a mig. I have done quite a few fin repairs like this now and all have worked out well.
Std m/s wire used I guess?
Any particular technique eg tack, then “stop/start” eg weld 1/2” then stop and let it cool) or just weld in one go?
Does the fin bend towards the weld due to contraction?
-
Yes just standard mild steel wire. Tack weld, no more than about 1/4" at a time them move to the other end and so on, takes time. If you hear it "tink" then you have welded too much in one go. I ground down the end where it is visible but left the weld elswhere, the fin doesnt seem to bend doing it this way. Its a slow process but has worked well for me. Once cleaned up and painted the repair is invisible.
-
That looks great,pity youre so far away
-
Hi All,
I repaired a badly (crash) damaged cylinder, the bike was T boned *eek* on the right hand side..
As the engine had been recently rebuilt I wanted to salvage as much as possible
Four or five fins were smashed as far as the core, I cleaned up the jagged edges and cut replacement fins from a Bantam cylinder. I opted to braze the replacement fins in place, pre heating in the barbecue and cooling very slowly
Despite all this the bore on that side distorted by 3-4 thou *sad2*
As the pistons that had been fitted were well scored due to too tight clearance, a rebore was needed anyway
John
-
That looks great,pity youre so far away
Did You preheat or post heat Brian please ?
If so what temperatures did You use /
Thank You .
-
No heating before or after. If I was welding with a flame or a stick welder I would pre heat but a mig puts very little heat into what your welding and by doing small welds at a time nothing warps.
-
Thank You Brian .