qkingston Posted November 25, 2018 Report Share Posted November 25, 2018 So can anyone recommend the best way to clean up the alloy cast rear training arms on 4A? I imagine normal grit blasting is no good Thanks David Quote Link to post Share on other sites
barkerwilliams Posted November 25, 2018 Report Share Posted November 25, 2018 David, I suppose it depends on what you are trying to clean off. Mine had been undersealed and needed a soak with white spirit. Then a long blast with water from a Karcher high pressure rotating tip nozzle, the standard pressure nozzle would not shift it. I used water because it would not damage or remove material from the arms. Alan Quote Link to post Share on other sites
stillp Posted November 25, 2018 Report Share Posted November 25, 2018 I used paint stripper, followed by alloy wheel cleaner. Pete Quote Link to post Share on other sites
qkingston Posted November 25, 2018 Author Report Share Posted November 25, 2018 ok thank, alloy wheel cleaner sounds like a good idea after an initial karcher blast! Quote Link to post Share on other sites
Richard71 Posted November 25, 2018 Report Share Posted November 25, 2018 I had mine done by an alloy wheel re-furbisher, grit/shot blasted and then powder coated, no damage done. Richard. Quote Link to post Share on other sites
RogerH Posted November 25, 2018 Report Share Posted November 25, 2018 DO NOT use shot. This is typically iron based and with stick into the ali and then go rusty. Roger Quote Link to post Share on other sites
graeme Posted November 25, 2018 Report Share Posted November 25, 2018 Glass bead blasting is best for aluminium parts. Cheers Graeme Quote Link to post Share on other sites
tim_trinda Posted November 25, 2018 Report Share Posted November 25, 2018 I had mine powder coated ... that was 15+ years ago and still looking good! I'm pretty sure they were shot blasted before coating...no sign of rust but I can see how this could happen as Roger says. Tim Quote Link to post Share on other sites
Dic Doretti Posted November 25, 2018 Report Share Posted November 25, 2018 Soda blasting should be gentle on the aluminium, Scottblast in Greenock do soda blasting. I have seen poorly applied powder coating start to peel off on the edges. Cheers Richard Quote Link to post Share on other sites
PodOne Posted November 25, 2018 Report Share Posted November 25, 2018 Cleaned mine with Gunk/hot water and then used a brass wire rotary brush on a drill. They came up nice and clean after which I painted them with Silver POR 15 but you could use clear if you wanted. Quote Link to post Share on other sites
Z320 Posted November 25, 2018 Report Share Posted November 25, 2018 I've been told not to powder coat them because this can make it difficult the realise cracks. And if you ever wanted to weld anythink that has been powder coated you think twice about it. So I cleaned them with a Karcher and did nothing else. Quote Link to post Share on other sites
RogerH Posted November 25, 2018 Report Share Posted November 25, 2018 9 hours ago, qkingston said: So can anyone recommend the best way to clean up the alloy cast rear training arms on 4A? I imagine normal grit blasting is no good Thanks David Hi David, if you have look inside you may well find that it is full (ish) of white corrosion products. It would be nice to have this removed. But it will come back. When I had my TA's off a couple of years ago I had the insides sloshed in Alocrom 1200 ( I worked on aircraft) https://www.lasaero.com/products/article/A00FWS9N9 This will stop corrosion in its tracks. Rather pricey for home use. But there are companies around that do it through the back door. Mine were done at a place in Uxbridge Hillingdon for £30/pair. Don;t powder coat the outside - as [er Marco's comments. Roger Quote Link to post Share on other sites
Dave McDonald Posted November 25, 2018 Report Share Posted November 25, 2018 10 hours ago, qkingston said: So can anyone recommend the best way to clean up the alloy cast rear training arms on 4A? I imagine normal grit blasting is no good Thanks David David, I've had mine blasted in the past, but stressed "gentle" material be used and can't remember if it was soda or walnut shells or similar. I was pleased with the results and then just sprayed them inside and out with silver cellulose when it was more readily available. Whenever you clean them of, by whatever method, give them a close inspection for cracks. A particular point of interest should be the machined face where the hub flange is bolted towards the bottom stud. Also check that all studs are secure. I have drilled mine out and fitted 5/16" UNC Helicoils and then fixed the hubs with cap head screws instead of studs. Dave McD Quote Link to post Share on other sites
ed_h Posted November 25, 2018 Report Share Posted November 25, 2018 These are actually pretty robust items. No need to avoid real (sand) blasting. The aluminum used in the casting was not chosen for cosmetic appearance, though. These were just blasted, epoxy primed, and painted. Ed Quote Link to post Share on other sites
DaveN Posted November 25, 2018 Report Share Posted November 25, 2018 I used a pressure washer inside and out then used Deoxidene to kill any corrosion followed by Alocrom1200. And got an alloy wheel finisher to give them a grit blast and powder coat them. Finished up with copious amounts of Astrolan before bunging the bungs in! As ed says they are pretty robust items, the only place I could see as a possible failure point is where telescopic shocks would attach, if the fillet radii are damaged. I think best left with the original lever arms. I did take a peek inside with a borescope before I started and considering their age and location and lack of bungs were remarkably clean inside. BTW we do use ‘shot’ of various grades on (high strength) alloy structures to improve the fatigue strength. Quote Link to post Share on other sites
stuart Posted November 26, 2018 Report Share Posted November 26, 2018 Regarding checking for damage these were scrap! (Looks like a UJ had let go) also other cracks. Stuart. Quote Link to post Share on other sites
RogerH Posted November 26, 2018 Report Share Posted November 26, 2018 A blob or two of JBWeld should sort that out Roger Quote Link to post Share on other sites
stillp Posted November 26, 2018 Report Share Posted November 26, 2018 Interesting! What had the spring been sitting on Stuart? Pete Quote Link to post Share on other sites
stuart Posted November 26, 2018 Report Share Posted November 26, 2018 2 hours ago, stillp said: Interesting! What had the spring been sitting on Stuart? Pete Probably nothing! Though from other evidence on the car this came from it had definitely been raced as there was evidence it had been fitted with Aeroscreens at sometime. Stuart. Quote Link to post Share on other sites
DaveN Posted November 26, 2018 Report Share Posted November 26, 2018 (edited) Blend out the crack on the web say 20:1. The crack on where the drive shaft passes through either weld it or make it into a slot and polish the edges. Tidy up the edges blend that ‘scollop’ on the top, send it to Roger for NDT and it’s good to go. Edited November 26, 2018 by DaveN Spellin’ Quote Link to post Share on other sites
stuart Posted November 27, 2018 Report Share Posted November 27, 2018 10 hours ago, DaveN said: Blend out the crack on the web say 20:1. The crack on where the drive shaft passes through either weld it or make it into a slot and polish the edges. Tidy up the edges blend that ‘scollop’ on the top, send it to Roger for NDT and it’s good to go. Long since in the scrap bin! Stuart. Quote Link to post Share on other sites
tim hunt Posted November 27, 2018 Report Share Posted November 27, 2018 Probably beyond JB Weld Roger, excellent as that product is, but I had a substantial crack repaired on a trailing arm 21 years ago and it is still going strong. I wanted to keep the old arm since it had been helicoiled for the hub attachment studs. I don't think any of the parts in Stuart's pics would have ben beyond a competent specialist Aluminium welder. Tim Quote Link to post Share on other sites
stuart Posted November 27, 2018 Report Share Posted November 27, 2018 7 minutes ago, tim hunt said: Probably beyond JB Weld Roger, excellent as that product is, but I had a substantial crack repaired on a trailing arm 21 years ago and it is still going strong. I wanted to keep the old arm since it had been helicoiled for the hub attachment studs. I don't think any of the parts in Stuart's pics would have ben beyond a competent specialist Aluminium welder. Tim The arms were also peppered with corrosion as well and as I had a pair of good ones in stock then it was only sensible to skip them, The other one was just as bad anyway as the bracket for the brake pipe was missing!. Stuart. Quote Link to post Share on other sites
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.