I was just looking through ways to prevent galvanic corrosion on a project we are working on. First off we are using aluminum inserts as hardpoints to thread into and mainly to distribute pressure. My big question is if we were to anodize the aluminum inserts will this prevent galvanic corrosion. I know fiberglass can be used to prevent contact but I would like to know if anodizing is a good alternative. Thanks in advance guys!
Greg Scrivner
Wouldnt it be easier to use stainless steel inserts, rather than aluminuim, especially if there is any need to remove threaded fastenings at any time in future?
…and Neverseize too?
I can rework some of the hard points to loose weight else where and also the thermal expansion would be down if stainless steel were used. Also for threading it is harder and less likely to be threaded incorrectly. Those are very good points that you guys mentioned. But the main reason aluminum was used was due to weight which is a major concern. Secondly aluminum is used due to cost, using stainless steel the price more than doubles for the pieces. So again would anodizing the pieces prevent galvanic corrosion from occuring. The metal parts are in a high risk area of coming in contact with fluids particuarly gasoline, oil, antifreeze, and water. Also the parts will have to stand up to a fair amount of abuse, so will the anodizing finish of a tendency to wear. So you understand some more the parts are being used as part of a carbon fiber intake manifold assembly. So I guess I will ask do you think that using stainless steel is a more attractive alternative to using the anodized aluminum pieces, cosidering price (steel is twice the cost), wear (how long will the anodizing finish last, I understand this depends on the grade), corrosion (the steel in contact with fluids etc, the aluminum if the anodized finish fails and galvanic corrosion takes place). The parts life span is around 20 years so again your opinion on what material/solution is best. Thanks for all of the advice guys.
Greg Scrivner
Decorative anodising wont offer much protection at all, hard anodising would be better but here in the UK this is quite a costly process, and would very likely increase costs above that of stainless steel.
Personally I would look at using plated mild steel fittings, which with careful design wouldnt be much heavier than aluminuim, and would have less problems with corrosion.
Chris
I would just like to say thankyou for helping me work through this problem I got the material worked out and the cost down and we are going to use 316 Stainless Steel. Would wrapping the majority of the stainless steel in fiberglass offer any benefit keep in mind that some metal has to remain exposed for mounting surfaces, or is this overkill. My next question I have had a hard time finding. We need to make a dissolvable core so that when the final piece is cured we can dissolve the core and be left with a hollow piece. Some ideas that came up are various types of plaster and simply chipping/breaking then washing the plaster out after the part has cured. Another idea was to use a type of sculpting wax as it can be easily heated and poured into the shape we need and after a room temperature cure we will place the part into the oven to cure the resin at the higher levels and this in turn will melt the wax out into a tray. Let me know if any of these ideas are possible or if you have any suggestions. The finished part is load bearing (60 pounds) must be hollow (its a intake manifold) and must be smooth on the interior for good air flow. Again any ideas and suggestions are welcome! Thanks for your help guys!
Greg Scrivner