Joy worked in construction for 7 years alongside her husband (25+ yrs. experience)—working on pole barns, grain bins, and barn repairs.
A Fully Erected Grain Bin With Hopper
Main Rings of Sheets--Overview
The lower sheets are installed one ring at a time, with strict attention giving to proper lapping. A sealant in a rubbery tape form, called mastic, is applied at each seam. Drift punches are used to help lift and align the sheets. An impact wrench and box end wrenches are used to tighten the bolts. As with the first ring, this is a two-person job, with the impact wrench operator inside the bin, and the other person outside, holding the bolt heads steady with the box end wrenches. This job requires strong wrists, good dexterity, and good mobility.
Each ring of sheets is completely bolted together, then the bolts are tightened before proceeding to the next ring.
If you have not seen the article showing how to put together the first ring, please refer to it for tips on sheet lapping, sealant application, drift punch use, and tightening of bolts at seams. We include only a refresher course here.
Tools and Equipment Needed for This Stage of Construction
- Proper grain bin jacks--you must rent or buy these from a reputable grain bin tools source, or manufacture a set yourself if you're exceptionally handy with a welder
- Alternate way to lift the bin, if desired--crane, boomtruck, or large forklift (forklift for small bins only!)
- Lifting ring, large truck rim, or lifting halo
- Lighting if working at night
- Drift punches, medium length (10 inches at least)--1 minimum for each crew member
- 9/16-inch box-end wrenches (2 at least), with long handles
- High quality impact wrench, as you will give it a work-out
- Hearing protection--preferably ear-muff or electronic type
- Work gloves which allow for dexterity (optional)
- Comfortable work boots with decent tread, hard toes optional
- Work clothes which will not snag or allow you to get hurt easily
- Vice grips, high quality
- Slipjoint pliers (optional, but can be handy)
- Tool pouch/apron, or coffee cans/small buckets for hardware (a small pouch is annoying as it must be refilled often, and is hard to reach into)
- Mastic (a sealant for between sheets)--can be found using the search words: Single Bead Tape Roof Sealant Metal Sales
- A way to block wind from swaying or sliding the bin during work (we often use a semi truck and trailer)
- T-posts for driving in around the partially built bin during off-hours, or a suitable way to weigh the bin down at the peak (i.e. the boom of a boomtruck or crane)
- Forklift, ATV, or another way to move the sheets and other materials on and off the jobsite
- Storage building for bin components, if they must sit between building sessions
Work Conditions and Cautions
As with any phase of grain bin construction, great care must be taken each time the bin is lifted in preparation for the next ring. Winds and other weather conditions must be considered. If it is too breezy, cold, or hot, postpone lifting the bin. Instead, anchor it firmly, and play it safe. The rush to get a job completed is not worth anyone's life or body parts.
Adverse conditions lead to exhaustion, clumsiness, and mistakes. A cloudy mind and slow reaction times may prove hazardous to yourself and fellow crew members. Even if you are on a deadline, take short breaks for protein-based snacks, and stay hydrated. In very hot weather, consider supplementing with potassium, which may help you stay in balance and resist muscle fatigue.
Windage, and Staying Safe
Starting the Second Ring of Sheets
Before raising the bin to begin on ring #2, you must install the first section of the main ladder, if applicable. See below for how to do this step.
Scatter the appropriate number of sheets from the stack, facing them as much as possible the right way so getting them in position is simple.
Have all tools and hardware handy.
If there is a door in the side of your bin, naturally you'll have calculated from the instruction manual where it goes, so you know where to start. If there is no main door, only a manhole in the lid, start about halfway around the bin opposite of this, centering your first sheet on a previous seam above it.
Starting Off Right
Basic Punch Use
Impact Wrench Tips and Notes
What to Aim For
With a high quality electric impact, you should be able to tighten 3 nuts per second or more during re-assembly. Have a person on the outside with 2 box-end wrenches holding the heads of the bolts as you tighten the nuts. 5/16 nuts should only be tightened around 22 foot pounds, and I normally go a little more. 3/8 nuts should be tightened around 38 to 42 foot pounds. On a 48' diameter bin, the black impact socket will often turn cherry red by the time a ring is completely tightened. Remember, tighten the nuts, not the bolts. You may need good gloves and rags to hold on to the impact after a while, as the gun will get extremely hot.
Jepson impacts (now out of business), are my favorite brand. Their impact wrenches out-perform any other gun on the market. They do not seriously over-heat, and they take the abuse.
If you cannot find a Jepson, a DeWalt or Milwaukee are your second best options.
Electric vs. Pneumatic
On a big bin, both types of impact guns give problems. If you are working fast, a pneumatic wrench will get very cold or freeze up. This is extremely uncomfortable to hold, even if the gun still works.
Also on a big project, an electric impact will overheat and possibly fry. You may continue to use a hot gun by wearing gloves and wrapping the handle in rags so you don't burn your hands.
There is no good solution to these problems if you want to work fast.
Additionally, a pneumatic gun will not keep up with the demands of an experienced builder even with a decently big air compressor. The compressor will need to refill frequently, forcing the crew member to stand idle waiting for it.
Second Ring--Techniques and Tips
Hardware Tightening Specifications
How much to tighten the nuts is determined by the size and grade of bolts, as well as their position. Please refer to your manual for torque specifications.
For this bin, the wall sheet bolts were 3/8-inch, and their steel quality was 5 grade.
⅜ on walls=38 foot pounds.
In general, you want to tighten the nuts until they are singing soprano.
Listening carefully will soon allow you to determine by sound how much is just-enough versus too much torque. Try not to strip bolts, but don't under-tighten them, and so give yourself problems in the future. Leaks are no fun to fix, and nobody wants spoilt grain (or a leaky grain bin home).
Stiffeners=looser, due to up and down movement making parts more fragile. 32 foot pounds on ⅜ bolts, and 17 foot pounds on 5/16 bolts.
The remaining rings are built and tightened similar to the first and second.
Sealant is applied on horizontal seams whenever the guage of the sheets changes. This may be more frequent or less frequent depending on the diameter and height of your bin. Heavier sheets are required on the lower rings to ensure strength as the pressure of the grain increases.
Stiffeners should be installed if you have any doubt that your bin will withstand the weight. These are U-shaped vertical iron pieces bolted onto the outside of the bin at intervals. Install them now if needed, as not only do you risk damage to your bin if installation is delayed, but it is much more difficult later, especially if your bin is on a hopper.
No Stiffeners Here
At this time, I am not prepared to talk more about stiffener installation. Just use common sense, and avoid using them where ground tremors occur, as the bolts may sheer due to vibration.
Walls and Floor Grain Bin Construction
Before you begin building your bin, think about the best way to protect it from wind damage during non-construction hours. The last thing you want to be responsible for is a grain bin shaped kite rolling through someone's yard. As your bin continues to be built taller, the danger of this happening increases. A nearly-built bin is a hazard.
Please take every precaution to protect both your investment and people throughout the building process.
Below are some ideas for stabilizing your bin during off-hours.
Make beginning work the next time as simple as possible. Leave your worksite uncluttered, and make the next-day's materials easy to get at while they are in storage. Keep tools picked up and in good working order.
Be sure not to completely install the last sheet of a ring prior to pausing. As shown below, tack it with bolts so you can get back into the bin without fuss, to set the lifting ring, etc.
Pausing for the Day
Changing Lifting Methods
Because our forklift was not big enough to use to finish building the bins shown in this article, we were forced to change our method toward the end. Our forklift boom extended only far enough to complete five rings of a six-ring bin. So we hired a crane while building the last ring and setting the bins on a hopper. If you cannot change methods on short notice, choose the lifting method that will allow you to finish your project with a minimum of fuss.
As we required a crane to set the bins on hoppers, jacks were out of the question for this project.