novice needs help

By Michaela521 Date 12-03-2005 05:59

First of thanks for the excellent help you provide here. I have a couple of questions that I needed cleared up so I can know what I am doing better.

1. What is a better method to use in your professional opinion with the pros and cons of each between using a rod and flux combination versus using a flux core rod.

2. What is better to use for general work in you opinion between mapp gas/oxygen combination versus an acetylene/oxygen combination. If you could include the pros and cons of each like pricewize and other comparisons. I understand that the acetylene/oxygen combination will produce a hotter flame and therefore you can do work faster but perhaps slower heating will produce better results when brazing/welding an item and also it might be cheaper even though it takes longer. Anything else to mention?

Again thanks for the help and I hope that I am not asking for too much:).

By billvanderhoof (****)

Date 12-03-2005 06:51

1- I like the flux in the can. I think it allows me to control the amount better but it may be just habit since thats how I first learned. I'm sure as many others will like the coated rods. Try both, choose the one you like.

2- I've never used mapp.

Bill

By jwright650 (*****)

Date 12-03-2005 11:41

1) I'm like Bill, in that I learned on the canned flux and haven't used the coated rods enough to say whether I like it better or not. Been a long while since I had to weld anything with Oxy/Fuel.

2) I've only used Oxy/MAPP for cutting, so I'm not sure how it works for welding, but brazing shouldn't be a problem at all. I do know that MAPP is the cheaper of the two fuels that you mentioned.
John Wright

By weldo

Date 12-04-2005 08:14

I have most often used the coated rod, and have always had pretty good results, i have used the rod and flux method as well with good results also, it boils down to individual preferance.
On the MAPP, I have never used it myself, but here is some info. I found that might help.
Steve

MAPP gas is liquefied petroleum gas mixed with methylacetylene-propadiene. MAPP is the tradename for a product of the Dow Chemical Company.

The gas is used for welding due to its high combustion temperature of 2927 °C (5301 °F) in oxygen. Although acetylene has a higher welding temperature (3160 °C, 5720 °F), MAPP has the advantage that it requires neither dilution nor special container fillers during transport, allowing a greater volume of welding gas to be transported at the same given weight. Also, MAPP is advantageously used in underwater welding, which requires high gas pressures (under such pressures acetylene decomposes to explosive hydrogen and carbon, making it dangerous to use.)

The gas is also used for brazing and soldering, under combustion in ambient air, where it has considerable advantage over competing liquid petroleum gas (i.e., propane-based) fuel due to its higher combustion temperature. A typical MAPP gas brazing operation would involve using it to silver braze (sometimes colloquially and inaccurately called silver solder) steel parts together.

MAPP is colorless in both liquid and gas form. The gas has a pronounced garlic odor at concentrations above 100 ppm and is toxic if inhaled at high concentrations.

By aevald

Date 12-04-2005 08:50

One thing you might consider when you are considering whether to use the prefluxed rods versus the rod and flux in a can is your degree of usage. If you do a lot of brazing the prefluxed rods can be very beneficial and convenient, on the other hand if your use is just every once in a while you will need to consider storage for these rods so that the flux doesn't deteriorate while they aren't in use. Cost for prefluxed rods is considerably more than for bare rods and a can of flux. As far as the gas combinations go, the other gentlemen that have posted here have given you plenty of information regarding the pros and cons associated with the two choices. The only other thing that you might consider when comparing gases is the difference in the hardware end of the equipment required to use one over the other, if you are already set up to run oxy-acetylene you may need to purchase special welding or cutting tips to run with the Mapp gas, the same would be true if you already have a Mapp gas set-up, you might need to purchase special tips to operate with oxy-acet, even hose requirements differ in some cases when using oxy-acet or other oxy-fuel combinations. There are hoses that are specifically designed for oxy-acet. usage and then there are hoses that are designed for oxy-fuel use. If you have an oxy-acet. hose don't use it for oxy-mapp gas, you get the picture. Good Luck! aevald