re-welds calculation

Date 03-19-2003 09:16

Hi to you all.I would like to know how do you estimate the cost of welds.I work along some machanical engineers,they knows nothing about welding.we have some ammonia pipes to change and some new compressors to install.we were advised to use tig {er-70s-2}for the root pass and smaw with 7018 electrodes for the filler and cap on carbon steel,seamless pipes.{1"through to 10"}with 10% ex-ray I want to have an idea of the method used for costing and also is this advise meaningfull.thank you for a response.

By Michael Sherman (***)

Date 03-19-2003 11:24

The best way to bid a job is to have done the work or atleast similiar work before. The second is to have an employee who has done it. The third is to evaluate each job that needs done individually, assess your personal, your equipment and calculate the time and material involved. Business owners and estimators usually take many years of trial and error to learn how to bid a job, it is probably not something you will learn on the internet.

Mike Sherman
Shermans Welding

By Niekie3 (***)

Date 03-19-2003 17:56

Hi

There are commercial software applications available for estimating welding costs. You will however have to pay for them (usually) and they are also not "fool-proof". At the end, if you put garbage numbers in, you will get garbage numbers out.

To answer your question more directly though, you will have to follow approximately the following methodology.

1) Calculate how much weld metal you will have to deposit of each process. (Typically you would do this per joint size and type, so that you can also calculate "unit rates".)
2) Get reasonable deposition rate data from the filler metal suppliers or other sources. (Typically given in kg per hour. (or lb per hour for those working in imperial units.))
3) Estimate a typical % arc-on time for your workshop. (e.g. 10 - 30% for much manual work such as pipe welding.)
4) Calculate the amount of time it will take to complete the welds.
5) Calculate a "cost" rate for a welder's hour, based on the salaries paid, and the overheads for the business.
6) Calculate the manpower costs from the info above.
7) Calculate the consumable costs based on the info above.
8) Add them together and you have a "cost" rate for quotations. Add the desired profit margin and you have the cost to quote.

All the above is based only on the welding opperation. If you are also providing the material, then you need to take this into account. If you are installing the lines, then you need to take that into account. If you are transporting them, take that into account, If you need NDE and other inspection, you need to add that etc.....

Hope this helps

Regards
Niekie Jooste