hey all! i have a question about using the eastwood rust converter on my 63 chevy c20 frame and cab....which is VERY rusty but still has potential...

How rusty can the frame be and still realistically benefit from using eastwoods products, or just these type of products in general (kbs, rust bullet, etc...)?

to put it in other words...are these rust prevention/conversion products for a frame with minor surface rust that only started to rust a year ago.....or will they actually work as well as we all hope they will with the realistic type 40 year old rust that we all usually see???

any insight would be much appreciated, and/or some pics if available??:)