MP 229

OPERATION AND

CON STRUCTION

COOPERATIVE EXTENSION SERVICE, University of Arkansas, U.S. Department of Agriculture, and County Governments Cooperating

Rope Wick Tips By DENNIS R. GARDISSER

Using selective applicators to control weeds growing above the crop has been widely adopted as a weed control method. Several types have been developed. Among them are recirculating sprayers, roller applicators, carpet wipers, and rope wick applicators of several designs. The most popular rope wick design is one developed by J. E. Dale from the USDA's Southern Weed Science Labora­tory at Stoneville, Mississippi. It is a simple design, but by no means the only one that can be con­structed.

A rope wick applicator works the way the name suggests. The chemical is wicked from a reservoir to the exposed portion of the rope. This exposed portion of rope is then wiped against the plant to be controlled.

Herbicides Used in Rope Wick Applicators

The development of Roundup (glyphosate) rekindled the interest in wipe-on type applicators. Other chemicals such as Banvel (dicamba) and 2,4-DB are also used. Always read and follow label instructions.

Selective applicators should be viewed as a method to supplement, rather than replace, other chemical and cultural weed control practices. This is because weeds compete with crops for up to 60 days to attain the required height differential. This may result in serious yield reductions with dense weed populations. The rope wick applicator cannot be used to control weed species that usually grow about the same height as the crop. The shorter species of weeds must be kept in check by conven­tional methods (cultivation or selective chemical control). "~I

Operating Tips Mounting .,.. Mount wiper at the front of tractor for

visibility and reduction of dust buildup.

2

Use hydraulic cylinders to control the wiRer height 2 inches above crop canopy.

The rope-reservoir assembly should rotate to get a rope position from 12 o'clock to 6 o'clock - 12 o'clock for transport, 2 to 6 o'clock for flow control (viewed from the right end). (See Figure 1 - ropes in the 5 o'clock position.)

Rope Wicking

Rate Manufacturer (oz/5 hr) Comments

Wellington Puritan Mills 2 Minimum flow

Gulf Rope & Cordage Co. "Pepperm int"

6 Reduced flow Pressurized systems

Gulf Rope & Cordage Co. "Pistachio"

13 Maximum flow

Use ropes with high recharge and load capacity. The Pistachio rope is the most widely used and best suited for most applications.

The best weed control is achieved with maxi­mum rope saturation.

Occasional drippage from wick ropes is desir­able. This indicates optimum rope saturation.

Reservoir Keep reservoir full for maximum flow.

Reservoir must be vented to avoid vacuum lock.

DENNIS R. GARDISSER is Extension agri­cultural engineer, University of Arkansas Cooperative Extension Service.

Reservoir length should not exceed 20 feet for level ground.

For sloping terrain, reduce reservoir lengths to ensure all rope ends are submerged. Reservoirs with compartments as short as 18 to 24 inches across the boom may be necessary.

Reservoirs may be separated at the center and mounted on pivoting frames. This allows the reservoir to be positioned along side the tractor for transport.

An extra compression fitting may be placed at the bottom of the reservoir on one end and plugged off. This allows a drainage hose to be connected for easy draining and cleanout. Treat this hose as a contaminated container and store properly.

Reservoir may be mounted to a rigid frame­work by large band-type hose clamps or similar devices. One clamp every 3 to 4 feet will pro­vide adequate support to avoid sagging.

Speed

Sparse weed infestation 5 mph maximum

Severe weed infestation 2.5 mph

Trips Two applications, both in the same day, are recommended for best coverage.

Second application is in opposite direction of the first.

Cleaning

Pressure wash rope wicks with strong stream of water daily.

In dusty conditions or when wiping milkweed, wash when buildup occurs.

f:'

Treatment Timing Treat when weeds are 6 to 10 inches above crop canopy.

Avoid wiping weeds when foliage is dusty or wet from dew or rain.

If rains occur within six hours after treatment, retreatment may be necessary.

Fluid Flow Control

The wicking action may be controlled some­what by:

Tractor ground speed Tightness of compression fittings Relative position of ropes (3 0 'clock - slow and 5 o'clock - fast) viewed from right end of reservoir Fill cap venting (very limited and response unpredictable.) Reservoir must be vented. Amount of fluid in reservoir Rope wicking capacity Pressurizing reservoir Length of exposed rope segments (shorter segments for faster flow)

Herbicide Solution

Always read and follow label instructions.

Premix 2 parts water and 1 part Roundup (glyphosate) .

Mix only enough for one day's use. Reduced activity may result from use of any leftover solution.

To Increase Wick Flow

You may use a combination of the following procedures:

Pressurized reservoir.

Loosen cap or vent (if equipped with vent).

Increase level of fluid.

Loosen compression fittings.

Rotate rope down to 5 o'clock position.

Install rope with higher wicking capacity and/or shorten length of exposed rope.

Reduce ground speed.

Occasional dripping from the ropes is desired. This indicates the ropes are reaching saturation.

3

4

r;:~~~ --------- Loogzn cap or vent .~ (if equipped w/vent)

Reservoir :;'JJJJ.-_ib-l ~~2I;;;;C;;;;:;;c=;;::;~~~_-lncreaselevel of fluid

corrpression fittings Figure 1. Methods to increase the

flow of liquid through Fbtate ropes down to the rope to have a higher 5 oclock tJOsitionsaturation level.

* Reduce grou nd speed '- Install rope with higher* OccassionClI dripping is desired. ""wicking capacity and lor

This indicCltes the rop2S are shorten length of exposed ropereaching SClturaton.

To Decrease Wick Flow Rotate ropes to 3 o'clock position.

You may use a combination of the following Install rope with lower wicking capacity and/orprocedures: increase length of exposed rope.

Lower fluid level (do not reduce below ropes).

Tighten compression fittings. Tighten fill cap or vent (if equipped with vent, complete closure may cause a vacuum to develop and restrict flow too much). Increase ground speed.

L-~~~J--__ Tighten fi II cap or vent ----------'if equipped with vent)

* Increase ground speed ~Ii~ RotClte rop<2S to 3 oclock position

Install rope with lower ~P4-wickirg Crt p:lcity and or

k2ngthen exposed -rope Lovver fluid k2VQ I

(00 not nzduce below ropes) ~Tighten compression

-fittings

Figure 2. Methods to decrease the level of liquid flow through the ropes for less saturation.

Rope Wick Construction

Rope wick applicators are relatively simple with no moving parts. These may be made in almost any good farm shop. The cost is not high, and $10 to $15 per linear boom foot is a good esti­mate of the cost to construct a unit, excluding the carrier. A metal support frame and carrier may be made of scrap metal. A spare hydraulic cylinder may then be connected for an inexpensive unit. Tractors with front end loaders are easily modified to provide good carriers. Precise construction is a must to avoid leakage. Consider the purchase of an already constructed unit.

Item

pvc pipe - 1120, 3-inch thinwall - SDR 160PSI or

SCH 40, 260PSI

PVC end cap - 3-inch

PVC elbow - 3-inch

PVC female adapter fit­ting - 3-inch

Threaded plug - 3-inch

PVC glue & cleaner

PVC compression fitting for 3-inch pipe

(Body, cap & bushing) such as available from:

(PVC end caps & all other parts) & complete units

Supplier

Plumbing dealer

Plumbing dealer

Plumbing dealer

Plumbing dealer ting ­

Plumbing dealer

Plumbing dealer

Rodger Sales Co. P. O. Box 278 Lyons, MS 38645 (601) 627-7162 or

Sherman Shaw P. O. Box 5089 Monroe, LA 71203 (318) 325-4361 or

Bowman Mfg. Co., Inc. Route 3, Box 705 Newport, AR 72112 (501) 523-2785

How to Build a Rope Wick Applicator

Note: Read through this plan at least once before purchasing parts or beginning construction.

1. Obtain materials for constructing unit:

Function

Reservoir boom

To cap pipe end

Fill spout at pipe end

Fill spout

Fill cap

To seal PVC joints

Attach wicks

Compartmentalizes reservoir

*Order one extl1l if drain spout is desired. Wicking rope - ordered to Gulf Rope & Cordage Co. Wicks

desired wicking rate . .., P. O. Box 5516 (Pistachio - most Mobile, AL 36605 popular) (205) 438-3159

("Pistachio & Peppermint") or

Wellington Puritan Ind. Box 521

t Madison, GA 30659 Cat. No. G1032

Quantity Required

Boom length

1

1

1

1

1 can each

4 per 10 in. of boom with 8-in. exposure*

2 per section

For 8-in. expo­sure use two 18-inch lengths per 13 in. of boom length

5

6

2. Place cap and fill spout on reservoir using recommended PVC glueing procedure. Before drilling holes in pipe reservoir, scrub the areas to be drilled with fine sandpaper to facilitate drilling and installation of PVC compression fittings (Figure 3). Mark two chalk lines on the pipe for drill holes. Measure and scribe all hole locations before drilling (Figure 4). The top row of ropes should be 600 clockwise (viewed from the right end) from the filler cap.

Figure 3. Use fine grit sandpaper to clean reservoir surface prior to making location of holes to be drilled.

3. With a flat bore wood fit or adjustable hole saw, drill two rows of 15j16-inch holes at pre­scribed locations (Figure 4). Make adjustments in hole size to fit your particular fitting if needed.

8"Figure 4. ---li~"r-~~~ut ~_ '. Jt~ .foran __ a-inch .. rope ex, '3/4" 2 3" posure.

~fi IlJi¥D=t

4. After drilling, with a fine tooth half round rasp, remove PVC drillings from holes and smooth out hole edges (Figure 5). After com­pletion, tape the sides of the reservoir vigorous­ly with a rubber mallet, and shake all of the PVC litter out through the fill port. Glue on compression fitting bodies (Figure 6). Allow ample drying time.

Figure 5. Drill and holes for inserts.

Figure 6. When using glued fittings, be sure glue is on all can, tacting surfaces.

5. If the wicking rope is not precut, cut to desired length (18 inches for 8 inches of exposed rope as shown). For designs with more or less rope exposure, change the length and hole space as needed. Cut the ropes to the exposure length plus 10 inches to allow a 4-inch wick on each end inside the reservoir. Use a hot knife to avoid frayed ends (Figure 7).

Figure 7. Cut ropes to desired lengths. Exposed lengths plus 10 inches, or 18 inches for an a-inch exposure.

6. Installation of rope segments into pipe fittings:

a. Slip one PVC compression fitting cap onto each end of rope segment (Figure 8).

Figure 8. Place one PVC compression fitting cap over each end of the rope segments.

b. With an Elastrator or similar device, expand rubber O-ring bushings and slip one onto each end of rope segment. Place this ring approximately 4 inches from the rope end. Trial and error will tell the true place­ment. These should be positioned so that the exposed portion is taut after assembly. However, these ropes should not be tight because this crimps the rope where it leaves

Figure 11. Standard reservoir components assembly order.

the fitting and restricts the fluid flow (Fig­ure 9). If ropes are not preshrunk, they may shrink 10 to 15 percent and may con­tract and pull fittings off the reservoir. Soaking and preshrinking may be the key here.

Figure 9. Use an elastrator or similar tool to expand O-rings and place them on the end of each rope segment.

c. Install ends of rope segments into set of compression fitting bodies. Seat rubber O-ring in compression fitting body, and screw compression fitting cap onto body. Caution: Do not overtighten compression fitting caps. Adjust tightness to control flow (Figure 10).

Figure 10. Put approxi-~ mately 4 inches of rope into the reservoir. It is ----; held in place by the compression fitting. _

7. The design of the frame depends on how it will be mounted on the vehicle. The boom should move vertically to allow for different crop heights. It also should be mounted so that it can rotate to help regulate the flow rate.

8. After the assembly is complete, fill the reser· voir with water and check for leaks. Allow to stand full of water overnight if needed. Small leaks will be costly later.

NOTE: All steps do not ~'Pply to every situation. This is intended as a general guideline. Think of the end result before cutting, drilling, or glueing to avoid errors. Quality construction is essential. Leaky reservoirs quicJdy cost more than can be saved by making a unit yourself.

Optional Steps Additions to the basic unit are limited only by

the ingenuity of the designer. Included here are a couple of optional additions that may prove useful.

Filler Cap Vent - The filler cap must be vented to avoid a vacuum lock. This may be done by sim­ply loosening the cap somewhat. However, vibra- .. tions may change the initial setting, and flow regulation is unpredictable. A radiator drain spigot or similar device serves as a good venting device. Installation is simple; just drill and insert into the filler cap (Figure 11). An 8- to 10-inch vertical extension on the top of the spigot may be neces­sary to avoid spills during turns and operation on unlevel terrain.

Reservoir Drain - An extra compression fitting body may be placed on the opposite end from the filler cap for draining the reservoir and cleanout. This should be capped for field operations. To drain the reservoir, attach a drainage hose and rotate the drain fitting to the 6 o'clock position. Draining and flushing will be easy if the tractor is parked so the drain end is lower than the fill end.

Sloping Ground Use When rope wick applicators. are used on sloping

ground, the wicks on the high side quickly dry out as the fluid runs to one end of the reservoir. For minimal slopes, baffles may be adequate.

For sustained slope use, a compartmentalized reservoir may be needed. This may be done in several ways, and compartments as short as 18 inches may be necessary. There are many ways to do this.

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The author wishes to acknowledge Dr. Joel T. Walker of the University of Arkansas Agricultural Engineering Department for helpful suggestions and reveiw of this publication.

The information given herein Is for educational purposes only. Reference to commercial products or trade names is made with the under­standing that no discrimination is intended and no endorsement by the Arkansas Cooperative Extension service is implied.

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30,1914, In cooperation with the U.S. Department of Agriculture, 'Dr. Randel K. Price, Interim Director of Extension service, University of Arkansas. The Arkansas Cooperative Extension service offers Its pro­grams to all eligible persons regardless of race, color, national origin, sex, or handicap, and is an Equal Employment Opportunity Employer.

MP229-4M-3-86

One method is to use specially designed PVC

caps or internal end plugs that fit right into the end

of the 3-inch PVC reservoir. These allow individual

reservoirs of almost any length desirable to be

placed end to end. These PVC caps are available from Bowman Manufacturing. When using these,

use a compression fitting as the fill port. Place on

the reservoir so that it is on top (12 o'clock posi­tion) when the ropes are in the 3 or 4 o'clock posi­

tions (viewed from the right end). Insert 10- to 12­

inch durable plastic tube in this fitting instead of a

rope to avoid spills and provide venting. A small plastic cork with a 1/16- to liS-inch hole through it may be placed in the end of this vent tube to

keep out debris. (See vent tube on reservoir,

Figure 12).

gent/filler tube - 1 per section

End • Cap

Figure 12. When using a compartmentalized reservoir, the ends may be capped as shown. The rope segments are placed for a continuous wick as shown. A fill spout is needed on each reservoir segment.

Any other method that will give separate reser­voirs, along the boom, of the desired length is satisfactory.