Repairing a 1 hole in cast alum dash

The easiest thing of course would be to exchange it if that's possible. If not, I know of a couple of solutions. Don't know how much more money you want to put into it though. You can have someone with a plasma cutter and a circle attachment cut the hole perfectly round and take no more material out than necessary to make it
round. Have them cut a plug using the same equipment from another piece of like material. I'm guessing you have 4043. You can TIG the plug into place using filler rod and insuring that there are no 'low' spots. Take the weld deposit down until just above the finished surface and go to a fine stone or wheel. Make the final finish using a buffing or lapping compound so the transition zone of the weld and the parent metal will blend. If done carefully you will get a pretty good match. Finishing method is most important here. Another method would be to arc spray the entire surface after the hole is plugged and ground flat. The arc sprayed coating will cover the entire part and you can wire brush and polish until the desired finish is achieved. This will positively give a color match. I'd spray it at least .050" thick. I can recommend a couple of shops if you want.

Removing frozen bolts in the back of the dash with a propane torch is probably not best. You need to put lots of heat into the bolts quickly. The propane will cause the entire part to absorb heat and possibly warp the part. There is no danger of melting the aluminum with propane however. I recommend you try a penetrant called PB Blaster. We have it in our line as it's the best we can find by far. If you want to check our price the order desk is at 1-800-325-1568. Steve N. U.S. Alloys Company

I'm glad to get your note and I have some questions if you don't mind.

I printed your detailed answer to my inquiry on polishing the cast aluminum. I am very new to metalwork and I'm ignorant about materials and process. I studied the Eastwood catalog and located the materials you suggest (Tripoli Compound, 80 grit, 220, jewelers rouge and white paste etc). And I located buffing wheels. Here are the questions:

Do I need to purchase buffing wheels and mount them on a motor to buff and polish the dash? Can I use a flat block and do it by hand? and what would I apply the compound to if it can be done by hand with a flat block of some type? ...what material can be mounted on a flat block? Or, am I limited to buffing wheels as indicated in the catalog?

Will motor mounted wheels produce a level and flat finish?

I appreciate you steering me in the right direction... A polished dash on the 9N will look great, but I want it to appear flat without undulations and scratches etc.

Excuse my ingnorance, but as you suggested, this is a new adventure for me, and I appreciate the opportunity to learn in areas I haven't been exposed to in the past. Thanks in advance. 9N'er

one last question (for now):

What do you recommend for block sanding by hand? wet/dry paper...and block sand it wet?

or, place a compound material on the paper too (80 grit, upto 220?) and block sand with paper and compound?

I know, these are neophyte questions...but, I'm in a steep process of learning, and at the beginning of the learning curve for most things regarding this. thanks Al for your help. 9N'er