Frequently asked questions


How do I order stock tanks?

Please call for a dealer near you or call to inquire about potential dealership. (406) 538-9477

What size stock tank do I need?

 Please use the calculator from the South Dakota NRCS page (linked below) to help you figure out what size tank you need depending on your livestock situation.

Go to page: SD-ENG-47 for the calculator.

How do I order storage tanks?

Please call to discuss your needs. If you don't already have an NRCS/engineer drawing of what you need, please download the below diagram and fill , sign, and return either by mail:

Montana Fiberglass, Inc.

2063 Casino Creek Dr

Lewistown, MT 59457

By fax: (406) 538-9497


By email:

We require a drawing of fitting placement and a 1/3 down payment before we will start your order.

Blank Diagram

What is the warranty?

We provide a 2-year warranty against workmanship and materials. See warranty labels for required installation to maintain warranty. These labels can be found directly on your tank above the drain plug on stock tanks and near the manway on cisterns.

Warranty Labels

What are my drinker options for Insulated/Covered round tanks?

See attached diagrams. There are standard configurations for the 8', 10', and 12' rounds, or if you have another configuration in mind, you can fill and sign the blank one and mail or email a copy. These are rough drawings with the intent of showing that there are 8 panels to work with on each cover; this in no way means that tanks are 8-sided.  The 6' round only has 6 panels; we suggest no more than 2 drinkers for this particular size.


How do I use a repair kit?


Repair Kit Instructions


REPAIR KITS-Included in each:

  • 1- 20 x 38 square of fiberglass material
  • 1- quart jug of resin
  • 1- vial  liquid hardener (catalyst) 

Use 10ml to 25ml of catalyst per one quart of resin. (25 ml at 50 degrees, 15ml at 70 degrees, 10 ml at 90 degrees) If you have a smaller area to patch, mix the catalyst and resin accordingly-half to half, quarter to quarter. You will have 15-20 minutes to work with the material.

If using gelcoat too (this is a special request and goes on the inside of the tank), use clear catalyst instead of red. Same mixing ratio as above.

The air temperature should be at least 50 degrees. The warmer it is, the quicker it will set up. Repairs should set up in about one hour. Resin will only last approximately six weeks. No warranty will be given for anything over the shelf life.


STEP 1: It is necessary to sand approximately 3 inches on both sides of the break, just enough to roughen the surface so the glass will stick.

STEP 2: Cut the fiberglass matting to overlap the break – 2 to 3 layers thick.

STEP 3: Mix the quart jug of Resin and the appropriate amount of catalyst (above)  in a separate container you do not wish to keep; be sure NOT to mix more than is necessary to use within 15 minutes. The mixture will get hard and you won’t have enough to repeat the procedure if necessary. The redder the resin/catalyst mixture, the quicker it will harden. Saturate each layer of matting with your Resin mixture, using a brush you do not wish to keep, and place on your break one at a time, brushing out any air bubbles.

*Please remember that repair kits only have a guaranteed shelf life of 6 weeks in proper storage conditions.

If you have any questions on use of this kit, please feel free to call us. 1-800-889-3281