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Mild steel, DOM, Chromoly

Bajabugfred

Member
l have a general question on fabrication with these materials. I have been welding all types of materials for over 30 years. The more I get into fabricating beams, arms, and cages for Baja bugs I am trying to learn when to use the different materials. I know the basics of strength vs weight. I know for a street or play Baja bug mild steel works fine but as soon as you start over sizing and widening parts it is nessary to use stronger and lighter materials. What information I am looking for is I am starting to work on pre runners as well as going to eventually build a race car for my grandson. In building cages and going from say .120 mild steel to DOM do I use the same .120 or do I drop to .095 to save the weight but is it a strength comparison? The same if I use chromoly can I drop down to .088? Is there a general rule? Is there a chart or guideline to improve the strength and lighten the frame? I have made frames out of 1 3/4 .120 DOM , 1 1/2 .120 mild steel and mixed DOM and chromoly. Any direction or help is greatly appreciated.
 

Zac Reish

Well-Known Member
I don't think good fabricators or builders are going to take money out of their pocket and tell you how to build race cars on here.
 

baja stu

Well-Known Member
Get a SCORE rule book or go on line and look at Best in the Desert's on-line rule book. All race car cages for cars / trucks are outlined with the material size and wall thickness for the main structure. For instance, a car under 2,500 lbs can be made with 1 1/2" .120 wall Chromoly or DOM. Or you could go with 1 3/4" .095 wall chromoly or DOM. Mild steel tube has no place in race cars. The welded seam is a failure point. For the most part, if you are mig welding , use DOM. If you are tig welding, go with Chromoly. Smart tube placement and engineering will make for a strong and light car.
 

baja stu

Well-Known Member
HA, I am stuck at home with the flu and was bored. Might as well surf the net.
 

Bajabugfred

Member
I am sorry if I offended any one and I was not looking for any trade secrets. I know that a lot of you have spent a lot of time and money with your Research and development. I respect the knowledge you guys have and my intentions was not to take money from your pockets. I am new to this site and was not trying to step out of bounds but learn a little information. Stu the information you gave me was what what I was looking for. I will search for info on those sites. Remember we all at one time started out with very little experience and knowledge and we looked up to people like yourselves to get started. I am trying to pass on my welding experience with my grandson and we are learning how to build the next level of Baja bugs together. Once again thanks for both of your input.
 
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